There are three ways anybody sells web work and they are not interchangeable. Each one decides who pays when the thing takes longer than anybody thought, and it always takes longer than anybody thought.
Hourly
You pay for time. Simple, transparent, and the risk sits entirely on you.
If it goes twice as long, you pay twice as much. If your builder is slow or learning on your dime, you fund that. And you will find yourself hesitating to ask questions, because every question has a meter on it, which is a terrible way to run a project.
Good for small undefined work. Fix this, look at that, help me with a thing. Bad for building a whole website.
Fixed price
One number for a defined outcome. The risk moves to the builder, which is where it belongs, because they are the one who can actually estimate it.
The catch is that fixed price only works with a real scope. If nobody wrote down what is in it, you get change orders and resentment. That is not the model failing, that is nobody having done the paperwork.
And be honest that a good fixed quote has padding in it. It has to. Sometimes the builder wins that bet and sometimes they eat a week. That is the deal you both signed.
This is how I quote builds. From 1,000 on a custom site, from 6,800 on a store. Then we write down what that covers.
Retainer
A fixed amount monthly for ongoing capacity. Predictable for both sides, which is the whole appeal.
It works for maintenance, edits, small improvements, someone being available. Care plans are this. Workshop at 149 is ninety minutes a month, and if you do not use it, you do not use it, and I will tell you that rather than quietly bank it.
What a retainer is bad at is building something new. Do not let anybody put a redesign on a retainer and drip it out over eight months. That is a fixed price project wearing a subscription costume.
The question
Whatever the model, ask what happens if the estimate is wrong.
Who absorbs it. Under what circumstances would you come back to me for more money. What does a change order look like.
A straight answer to that is worth more than any of the three structures. A vague answer means you will be having that conversation later, at a worse time, with money already spent.