The Bernina store here takes trade-ins and they always have several good used machines for sale. Their service people go over them carefully, fix what's needed, and have a 30-day guarantee for these used machines. If you have to teach yourself to sew on whatever machine you get, it's going to be pretty trial-and-error, so try hard to find somebody who can assist you as you learn. Doesn't have to be a professional teacher, just somebody who's an experienced sewer who could help you with getting the necessary beginning skills down pat. If you get a used machine, be absolutely sure it comes with a manual, or check online to see if you can get one that way. Otherwise it's going to be a very steep learning curve and we don't want you to get discouraged.
No such thing as a silly question on this forum, so come back with anything that confuses you!