Wow, there is some...interesting... advice posted so far. If you haven`t already, look up the Motorcycle Safety Foundation, they are the ones that offer the courses through community colleges and Harley dealers.
The Basic Riders Course (brc) is invaluable. It is the best place to start and well worth the cost even though the cost seems outrageous at first. They will provide a helmet and gloves. You will need a long sleeved shirt, preferably a jacket with padding/armor, long pants, and over-the-ankle shoes. You`ll probably want a set of good gloves too for feedback an protection, I dont know about you, but I use my fingers a lot.
Do yourself a favor and keep the cowboy boots for riding horses, the heel isn`t great for shifting and they offer little support to your ankle should you take an impact. Buy yourself some good gear, it`s worth its weight in gold, even second hand. (Check craigslist and dcsportbikes.net for used gear). Never buy second hand helmets though. If you can`t afford riding gear, you can`t afford to ride, sorry to put it so bluntly. Motorcycling isn`t cheap and the only way you`ll actually save money is to get rid of your car.
Keep in mind that the BRC is just a starter course and barely makes you ready to be on a public street, most of it is done below 15mph and doesn`t train you for the idiots all around you. Once you`ve taken the course practice in parking lots and work your way up.
Try not to buy a fixer-upper or trashed bike as your first ride. It`s bad enough you`ve got inexperience working against you, the last thing you need is a busted bike too. If you`re afraid to mess up a nice bike then get good insurance, I recommend a company called Riders. There is an old saying, there are 2 types of riders, those who`ve dropped their bikes, and those who haven`t dropped them yet.
Avoid anything over 700cc for a cruiser and 500cc for a sport/sport-tourer at first. There are a lot of recent additions to the sub-500cc market over the past 5 years. If you are very comfortable on the bikes at the BRC then a 500 isn`t a bad place to start. If you are a bit shaken, there`s nothing wrong with a 250 and there`s always a market to resell them.
Lastly, I will gladly ride with you if you`ve got a good head on your shoulders and want to learn. I have 7 solid years of riding experience, none of those being a teenager or on a dirtbike.
Sorry for the super long post, hope it helps.