Thank you for wanting to rescue this kitty!
Cats can be expensive, depending upon their health. I don't want to discourage you, but you do need to be prepared for emergencies to happen, it's part of caring for a pet.
Cats do not smell. All you have to do is provide two litter boxes for one cat and clean them at least once a day. And you MUST have kitty spayed or neutered, or they will spray. The only thing that would cause a smell is if you don't keep the litter boxes clean.
A vet would be able to tell you how old the kitty is - size isn't necessarily and indication of age, just like with people.
Vet charges vary from area to area, but the initial visit and shots is usually several hundred dollars. They must have distemper and rabies shots, and you have to take the cat back for a follow-up distemper shot. Outside kitties usually have fleas and/or ticks and/or internal parasites, and if the vet recommends Revolution, don't do it, tell him you want to use Advantage for the fleas and ticks and Panacur if your kitty has round worm. I assume you want to keep kitty indoors only - then the Advantage would only need to be applied once. They should check for round worm by getting a stool sample and looking at it under a microscope (they can do this in the office, you don't have to wait for kitty to poop).
There is no way to tell what kind of personality a cat is going to have. If you're not prepared to have a skittish kitty, do not adopt one from outdoors. Best to go to a shelter or an adoption day, adopt an older kitty that's personality has already developed and tell one of the volunteers or shelter workers what you're looking for.
However, outdoor kitties can be socialized - it just takes time and patience on your part.
Imagine that you're three years old, you don't know what happened to your parents, but you're flown on a plane (which is scary) to China. You don't know whether or not your new family wants to eat you, use you for medical experiments or what. Everything looks different, everything smells different, everything sounds different. You're terrified.
That is the experience of an outdoor kitty brought indoors. It takes some time to earn their trust, and to let them get used to all the new sounds, sights, and smells. They don't know what love is, they don't know what play is, and they don't know what you want from them. They learn - and sometimes quickly, especially if they're used to being around people. We're caring for two feral boys that were over a year old when we brought them in to be neutered - and within a few weeks, even though we didn't adopt them to be pets and we released them back outdoors (it's called trap-neuter-release, and it prevents the cats from further procreation), they come twice a day for the food and pets - they love being brushed, and one of them just crawls up into my lap, and it only took a couple of weeks. But that is unusual - they've obviously been around people a lot OR they were not born feral (or both).
There are lots of things you can do to help them come to trust you once you bring him inside - but there is no schedule on which socialization happens, and you just have to be able to turn off all expectations and let kitty go at his or her own pace.
You can learn to communicate with your kitty, and they definitely understand what you're saying. Whether it's your tone of voice or what - they know. And they learn loving words of approval quickly, and they learn the meaning of the word "no" pretty quickly. But they ARE very independent.
Here are some sayings that are very true:
"Dogs come when called - cats take a message and get back to you."
"Dogs have owners, cats have staff."
"A cat will be your friend, but never your slave."
"There are people who reshape the world by force or argument but the cat just lies there, dozing, and the world quietly reshapes itself to suit his comfort and convenience."
"Cats seem to go on the principle that it never does any harm to ask for what you want." --Joseph Wood Krutch
"The last thing I would accuse a cat of is innocence." --Edward Palley
Cats are all about "me" and that's why we all end up spoiling them so, because a happy, purring, smiling cat warms the heart like nothing else.
...and that is the trick to "teaching" them what is OK and not OK. There is no disciplining a cat - it doesn't work and it just makes them fear you or dislike you. Unlike dogs, they don't necessarily go out of their way to please you. They are all about redirection and positive reinforcement. And we can help with that on this site too.
Hope this helps - and if you decide to go for it, we can help with socialization tips.
BTW - are you in Gainesville? They have a great student run TNR (trap-neuter-release) program, and you should try to contact them to let them know about where these kitties are hanging out just in case they're not already working in that area.
Here's a link to an article on it in the meantime: http://www.straypetadvocacy.org/html...feral_cat.html