Fixed price vs time and materials for an MVP

By Malik Chohra

Use fixed price when the scope is clear and the budget is the thing you most need to protect, which is true for almost every first MVP. Use time and materials when the work is genuinely open-ended: ongoing iteration after launch, exploratory research, or a build where the scope will obviously change every week. The mistake is not picking the wrong model in the abstract. It is signing a fixed-price contract on a vague brief, or running a time-and-materials engagement with no cap and no visibility. I quote both at CasaInnov, fixed price for scoped MVPs and $100 an hour for open-ended work, so here is how I decide which one a project gets, and what protects you inside each.

What the two models actually mean

Fixed price

You agree a defined scope and a single number up front. The vendor carries the risk of estimation. If the build takes longer than expected, that is their problem, not your invoice. If it goes faster, they keep the margin. At CasaInnov the Vibe Coding 2-week MVP is fixed at $8,999, and scoped blocks of work start at $3,499 fixed. Fixed price only works when the scope is written down precisely, because the number is only as honest as the brief it is priced against.

Time and materials

You pay for hours worked at an agreed rate. At CasaInnov that is $100 an hour. The scope can flex week to week. You carry the estimation risk: if the work runs long, the bill runs long. In exchange you get flexibility, you can change direction without renegotiating a contract, and you do not pay a risk buffer baked into a fixed number.

When fixed price is the right model

Choose fixed price when:

• The scope is clear. You can describe the core loop and the screens. A vendor can read it, quote it, and commit. This is most first MVPs.
• Your budget is hard-capped. You raised a specific amount and you cannot afford an open-ended bill. Fixed price moves the overrun risk onto the vendor, which is exactly where a budget-constrained founder wants it.
• You want a deadline that means something. A fixed price tied to a fixed scope and date forces both sides to agree what "done" is before work starts. That clarity is worth as much as the cost certainty.
• You do not have a technical person to manage hours. Time and materials needs someone on your side watching the burn. If that is not you, fixed price removes the need.

The whole reason a two-week MVP can be sold at a fixed $8,999 is that the scope is bounded: one core loop, auth, payments, store submission. I can commit to that number because I ship on a pre-wired stack and I know how long each piece takes. The mechanics of how that timeline holds are in my two-week MVP playbook.

When time and materials is the right model

Choose time and materials when:

• The scope will obviously change. Post-launch iteration is the clearest case. You do not know which feature next month's user data will demand. Fixing the price would mean fixing the wrong scope.
• You are exploring, not executing. A research spike, a proof of concept, a "can we even do this on-device" question. There is no defined deliverable to price.
• You have technical oversight. A CTO, a technical co-founder, or a senior reviewer who can watch the hours and steer. With oversight, time and materials is the cheapest model because you pay for exactly what you use and no risk buffer.
• You value flexibility over certainty. If changing direction mid-build is likely and valuable, a fixed contract becomes a tax on every change. Time and materials lets you pivot without a change-order conversation each time.

Most of my clients move from fixed to time and materials after launch. The MVP is fixed-price because it is scoped. The iteration that follows is hourly because it is not. That hand-off from one model to the other is the natural shape of a healthy engagement.

The trap inside each model

Both models fail in a specific way, and knowing the failure mode is how you protect yourself.

The fixed-price trap: a vague brief

Fixed price priced against a fuzzy scope is a fight waiting to happen. Every ambiguity becomes a change order. The vendor padded the number to cover the risk, so you overpaid, and you still argue about what was included. The fix is to write the core loop and the screens down before you ask for a number. A precise brief makes fixed price honest. If you cannot write the brief yet, you are not ready for fixed price, you are ready for a small paid scoping block.

The time-and-materials trap: no cap and no visibility

Hourly billing with no cap and no weekly reporting is how a $20,000 project becomes a $70,000 surprise. The fix is structural: agree a not-to-exceed cap, get a weekly burn report, and review scope at every milestone. A vendor who resists a cap or a weekly hours summary is the vendor you should worry about. I send burn reports without being asked, because a founder who can see the hours trusts the invoice.

The hybrid most healthy projects use

In practice the cleanest engagements are not pure either-or. They are fixed price for the bounded build, then time and materials for the open-ended life after it.

1. Fixed-price discovery or scoping block from $3,499 to turn a fuzzy idea into a written, quotable scope. Cheap insurance against the vague-brief trap.
2. Fixed-price MVP build at $8,999 for the bounded two-week scope, so your budget is protected through the risky part.
3. Time and materials at $100 an hour for everything after launch, with a monthly cap and a weekly burn report, so iteration stays flexible without going open-loop.

That sequence gives you cost certainty exactly where you need it and flexibility exactly where the work demands it. It is what I quote most often, and it is what I would tell a founder to ask any vendor for.

FAQ

Is fixed price or time and materials better for an MVP?

Fixed price is better for a well-scoped first MVP, because it protects a hard-capped budget and forces both sides to agree what "done" means before work starts. Time and materials is better for open-ended work like post-launch iteration or research, where the scope will obviously change and a fixed number would lock in the wrong scope.

What is the risk of a fixed-price contract?

The risk is signing one against a vague brief. Every ambiguity becomes a change order and the vendor pads the price to cover estimation risk, so you overpay and still argue about inclusions. The fix is to write the core loop and screens down precisely before asking for a number, or to buy a small scoping block first.

What is the risk of time and materials?

An open-ended hourly bill with no cap and no visibility, where a $20,000 project quietly becomes $70,000. Protect yourself with a not-to-exceed cap, a weekly burn report, and a scope review at every milestone. A vendor who resists a cap or weekly hours reporting is a warning sign.

Can I combine both pricing models?

Yes, and the healthiest engagements do. Fixed price for a scoping block and the bounded MVP build, then time and materials for iteration after launch with a monthly cap. At CasaInnov that is a $3,499 scoping block, an $8,999 fixed MVP, and $100-an-hour ongoing work with burn reports.

Why do vendors prefer time and materials?

Because it moves estimation risk onto the client. That is fine for genuinely open-ended work, but for a bounded MVP a vendor who only offers time and materials may be avoiding the commitment a fixed price requires. A senior studio that knows its delivery time can quote fixed price on a clear scope without fear.