a marketplace app for 500 users
PROJECT OVERVIEW
What this app does
A marketplace app for approximately 500 registered users, enabling sellers to publish item listings and buyers to browse those listings and place orders. The MVP provides the essential closed loop of listing management, marketplace discovery, purchasing, and order review without assuming unstated features such as online payments or messaging.
As an anonymous visitor, I can browse active marketplace listings so that I can discover available items
As a buyer, I can browse and view listing details so that I can choose an item
As a buyer, I can place an order for an available listing so that I can purchase it
As a buyer, I can review my orders and cancel an eligible open order
As a seller, I can create and update listings with images so that buyers can discover my items
As a seller, I can review incoming orders and update or cancel eligible orders
The following user counts are projected totals after one year of growth
100
sellers
Registered users who publish listings and manage incoming marketplace orders.
400
buyers
Registered users who browse listings, place orders, and review or cancel their purchases.
1000
anonymous_visitors
Public visitors who can browse active marketplace listings without an account.
COST BREAKDOWN
How your requirements become a plan and a price
Momen doesn't give a vague quote: it first sizes the project's actual demand for each capability and resource, then costs each item out. The numbers in the 'Project demand' column below — their scale assumptions and derivations — are detailed in Scale & sizing
Minimum viable plan
PRO
Marketplace purchases require payment collection, so the minimum selection is PRO.
See the capability-by-capability assessment ▾
PROJECT DEMAND
ALLOWANCE PROVIDED (COMPOSITION)
AI points add-on
x 0
0 points
not purchased
(plan/kit 5.0M points)
No requirement
$ 0
Outbound data transfer add-on
x 3
121.85 GB/mo
500GB × 3/year, amortized monthly
(plan/kit 10.00 GB/mo + add-on +111.85 GB/mo)
Add-on fills +111.85 GB/mo gap beyond plan/kit
$ 8.75
Object storage
add-on
x 1
24.42 GB
100GB × 1/year, amortized monthly
(plan/kit 10.00 GB + add-on +14.42 GB)
Add-on fills +14.42 GB gap beyond plan/kit
$ 2.92
Database storage add-on
x 0
113.57 MB
not purchased
(plan/kit 1.00 GB)
Covered by plan/kit (margin ~781%)
$ 0
single-tenant kit
x 0
1 req/s
not purchased
(plan/kit 25 req/s)
Covered by plan/kit (margin ~2400%)
$ 0
PRO
x 1
Pro is the minimum viable plan
Pro
(Plan tier: PRO)
See minimum viable plan above
$ 99
plan + add-ons · usage-based · no development cost
WHY MOMEN
Your options for this project
In the table below, the 'monthly infrastructure' for the self-built / AI routes is derived from the AWS list prices shown below, sized against this project's actual usage. Figures cover infrastructure and operations only — AI usage is billed separately and excluded here, so they don't match the $110.67/mo all-in above.
Current usage sizing
AWS list pricing
0.00 GB (first 100GB free)
Internet egress → 0
24.42 GB-month
S3 Standard → 0.56
0.11 GB-month
RDS gp3 storage → 0.01
2 × db.m6g.large (Multi-AZ) × 730h
RDS PostgreSQL db.m6g.large → 232.14
2 × t4g.large × 730h
EC2 t4g.large → 98.11
Total ≈ $330.83 / mo
Pure cloud resources
DEVELOPMENT COST
MONTHLY CLOUD INFRA ($/MO)
MONTHLY TOTAL (INFRA + OPS, EXCL. AI USAGE)
Traditional outsourcing / build in-house
about $70,000 - $110,000
≈ $331
Based on the AWS estimate above
≈ $2,331
Infra $331 + ops ~$2,000
4-6 months
5 / 5
Vibe Coding
about $12,000 - $20,000
≈ $331
Based on the AWS estimate above
≈ $1,831
Infra $331 + ops ~$1,500
hours
5 / 5
AI full-stack generation
about $5,000 - $9,000
≈ $331
Based on the AWS estimate above
≈ $1,831
Infra $331 + ops ~$1,500
hours
3 / 5
Off-the-shelf SaaS / vertical solution
$0
N/A
Priced per seat, not by cloud infra
≈ $16,000+
Per-seat pricing, tens of thousands of users
days
1 / 5
Momen
Recommended
$0
$111
All-in: egress / storage / auto-scaling; excludes AI usage
$111
hours
5 / 5
Servers, databases, traffic and storage are inherent infrastructure costs for this project — you pay them whether you outsource, use Cursor or Lovable, or build it yourself (self-built runs ≈ $330.83/mo at AWS list prices, often more), on top of the dev and ops staff you'd need to hire. Momen bundles all of it into $0/mo all-in and removes the need for an ops team.
The frontend can be generated with AI tools (Cursor, Lovable, etc.); the hard part is the backend — auth, database, scaling, data security and ops. Momen delivers a production-grade backend as a BaaS: keep the vibe-coding speed on the frontend, while the backend runs on proven infrastructure — reliable, with no self-hosting or ops.
SCALE & SIZING
What scale this estimate assumes, and how the numbers are derived
Cost depends heavily on usage volume. First see the key assumptions and business scenarios this estimate uses, then the full calculation derived from each scenario for every resource — all adjustable to your real situation
We assume 500 registered accounts because the project explicitly states that the marketplace should support approximately 500 users, which takes priority over the general marketplace category anchor. If your actual business operations differ, for example if the figure refers only to active buyers and excludes sellers, this parameter and group split can be adjusted accordingly.
We assume a standard linear-growth marketplace because a new app serving approximately 500 users would typically acquire accounts and listings gradually during its first year. If your actual launch differs, for example if it begins with a full pre-existing dataset or a concentrated recent campaign, this parameter can be adjusted accordingly.
Daily Buyer Shopping Period
Weekday Seller Operations
Daily Buyer Shopping Period
Daily Public Marketplace Browsing
30
times/month
0.1 req/s
Peak load
We assume registered-buyer activity is distributed across a four-hour daily shopping period because this marketplace has no scheduled sale or other strong synchronization signal. If actual demand is concentrated around promotions, the duration can be narrowed accordingly. Discovery, inspection, ordering, review, and cancellation are separated into distinct purposes because each has a different participant scale and intended core interaction.
Main impact: Peak Concurrency
The scenarios above set the assumptions for each resource; below is the full calculation derived from them. Click to expand each item.
DEVELOPMENT SCOPE
How this app works
What exactly does this budget support? Broken down by business scenario, showing the pages, data tables, automation flows and AI assistant behind each one
A seller creates and maintains a listing, then reviews and manages incoming orders.
Marketplace Browse Page
users
create_marketplace_order
A registered buyer discovers listings, places an order, reviews order history, and may cancel an open order.
Marketplace Browse Page
users
create_marketplace_order
An anonymous visitor browses the public marketplace catalog.
Marketplace Browse Page
users
page
data_table
action_flow
Seller Orders Page
Seller view for reviewing and managing incoming marketplace orders.
Seller Listings Page
Seller workspace for creating, viewing, and editing listings and listing images.
Buyer Orders Page
Personal order history and eligible order cancellation for buyers.
Listing Detail Page
Detailed listing presentation with its image gallery and order action.
Marketplace Browse Page
Public catalog of active listings with category and price filtering.
FAQ
What you might want to know about this project
The Q&A below is generated by AI based on this project's type, features and scale
How are multiple listing photos handled?
Is online payment included in this estimate?
Does the 500-user assumption include anonymous visitors?
What will most affect resource usage for this marketplace?
Copy to discuss with AI
Challenge & re-estimate
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