For the starting student freelancer, estimating how much to charge a client for a project can cause anxiety if you aren't sure what you should be estimating. It's easy to say "it will take me 20 hours to do this project" then just multiply it by your hourly rate, but you could be forgetting some very important factors. For instance, is your client easy to work with? What about how much admin time (i.e. invoicing, emailing, phone calls, contract setup, etc.) will be involved? Will your client need a lot of education along the way or are they fairly knowledgeable about the services you are offering?