I have experience running a car lot for 2 years. I cant help you out with taxes but I can help you with the finance part of it. You will of course need a credit application form, a finance form ( I used a california 552 2005 you can get at reyrey.com ) a transfer of title form (i used a 262 from the dmv) and other forms to protect yourself "as is" no warranty or maybe you will give them a warranty ( i suggest giving them a warranty at least a few months. I used and liked westlake financial becuase they have a website that lets you see if your customer is approved or not. Lots of customers are inpluse buyers and if they have to wait 2 hours they will go somewhere else where they can approve them now.