Okay, those photos tell a lot. Mostly that the bike is probably not worth fixing. If you're on a budget, don't buy new as you will just get a poor bike. Better to find a good used bike. Start by getting a bike that does not have a one-piece crank, like the one in the photo. Look for a bike with bolts that hold the chain rings and V-type brakes. After that, it likely starts to get expensive.
:)ensen.