Are you buying from the original owner? If so, ask to see all maintenance records. Ask to see the original purchase documents to ensure it was not stolen. If purchase documents not available, see if you can have the serial # checked by local law enforcement.
If you are buying from a dealer, find out what, if any, warranty you are receiving and whether you can return it if you change your mind when you get it home.
Before you give the seller your money, complete all inspections and tests that you might conceivably want to do.
I am buying from a dealer. I think it is a trade in. I agree it would be good idea to bring it home and try it out. Can't cut grass or plow a garden in the snow, but could play around with it. I guess it wouldn't be out of the ordinary to ask to bring it home.