I suggest you go to Sears and get a nice starter Craftsman set, if you dont already have one. You will need both metric and standard sizes of wrenches and sockets. If you get a big enough set, then you'll get some pliers and side cutters, too. All that should run you a couple hundred $$, maybe $300. The Craftsman tools have a very good warranty and you'll be happy with them. A 1/2" drive set is good to start with, since it usually goes from 7/16" up to 1-1/8" or more. The smaller 3/8" drive sets usually only go to 7/8" or so.
Then buy a nice grease gun. That'll cost around $15-25 and get several tubes of grease. I like Mobil XHP222 since it has some water resistance and it is a synthetic.
Lastly, get a whole bundle of tie wraps - those zippy things that you bind things together with. I love them, they are as good as duct tape. Get a few good ones (UV rated for outdoors) and lots of cheapos. Home Depot or Harbor Freight sells those.
A couple of funnels to help you change oil and a couple of good filter wrenches or slip type channel lock pliers. Of course if you dont have any Vice Grips get a couple of those, too. And a nice record book to help you keep track of what you did. Oh yeah, get a $2 pen light - they come in really handy to look into the dark spaces, like a gas tank and under your hood.
There! I helped you spend about $500.
Hint, if you want to go cheap, ask your friends or relatives if they have an old tool set you can buy from them ... or hunt the yard sales, too. Maybe run an ad in the paper wanting to buy a tool set...Rule of thumb is 10-50% of new for a used set of tools.
enjoy and glad to have you on the forum!