The deal with stuff like this is, you always charge more than you really think you should because the people are going to be difficult and would pay someone els

The deal with stuff like this is, you always charge more than you really think you should because the people are going to be difficult and would pay someone else more if you were with a larger firm. So I'd do an intake meeting with them to get a sense of their needs. Ask lots of questions, do your home work and figure out what they need. Then draw up a scope of work that outlines the work you're going to do and put a quote on that. Historically all jobs suck equally and they work you just as hard, so you might as well be compensated well for it and if it's too much and they balk, then it's fine. Someone once gave me advice that said if you really want to work on a project charge a lot and if you don't want to do it, charge more. I don't necessarily employ this advice, but...it's an interesting thinking. You don't have to justify anything. You're a professional who knows his craft and if you outline your recommendations and what you're going to do in writing -- which is what a firm would do -- then you're going to be fine. Realize if it's too high they'll go with someone else, so decide if you REALLY want the work or not. If you want the extra money, then decide how big the project is and come up with a total price and then divide that by how many hours you think it'll take realistically (in other words, more hours not less hours) and then quote them based on that hourly rate.