If you adopt a cat from many shelters, especially no-kill shelters, you can bring the cat back if there are problems. The one I volunteer with is like that.
There is a lot of info at this site:
http://www.fanciers.com/cat-faqs/index.html
One way to reduce vet bills is to keep the cat indoors only. This cuts out the fights, fleas or ticks, poisoning, being hit by cars, and other outdoor dangers. This site has more info: http://home.HiWAAY.net/~keiper/indoors.htm
You might want to consider getting an older cat (read: not a kitten). They aren’t as hyper usually, and many have already developed all of their behaviors that you would want to know about. They are already trained, many times.
Male cats are a bit more affectionate usually, and are cheaper to have ‘fixed’. Females aren’t as likely to spray but are more expensive to ‘fix’. Doing this has a lot of benefits:
http://ext.msstate.edu/ppe/news/news/cvm/neuter.txt
Good luck! Be sure to check out that petfinder link metioned in a previous message… a lot of the pets there are really nice and already trained.