Welcome yahoooniee, The experts above are all right. If all repairs went as planned, you'd likely have more than $300 in the bike just getting it road worthy. Unless you're in love with the bike, it may just be easier to buy one that's ready to ride in the $300 range. I'm sure there are quite a few C&V bikes in and around your area in that price range that would certainly fit the bill as transportation/project/investment bike. If you have any questions, just ask...

If you're looking for a first project bike, find something that just needs to be taken apart, cleaned, lubed, and reassembled. It'll be more fun, less hassle, and it'll give you a good idea of what to expect if you ever do buy one that needs a total overhaul. Good luck!