I'm a freshman in college and have agreed (informally) to help a local small business convert a large excel file into a format their new inventory software understands. I'm meeting with them in a week to determine whether their request is feasible, and then discussing terms of engagement if it is. We've discussed compensation and I've said I will charge a fee for the consultation and then some additional rate if there is any other work that can be done.
After this point, though, I'm lost. I don't know what to charge, how to invoice, or what kind of contract I need to write up. There is lots of info about this around the Internet, but it seems to be aimed at more established developers doing larger projects in higher cost of living areas. If I walk in with a 10 page contract asking for $300/hour they'll probably politely decline.
That in mind, does anyone have any advice on how to proceed?
$300/hour is way way way too much, even for a professional developer. You have no experience or formal education as a freshman, your rate should be max $50/hour.
You don't need any contracts, just get half of the money up front and if they screw you over, well at least you got that. When you give them the quote for your work, have each party sign the quote - that's your contract.