Here's the best piece of advice I can give you -- go to Trek in Shadyside, and have them fit you to a bike. THat will give you a really good idea of all the things you need to consider -- from basic frame size to the distance to the handlebars, width of the handlebars, etc. For someone new to the sport, you need to actually have a hands on discussion with someone who knows what they are doing. If you buy the wrong bike, or a bike with one critical component that is misadjusted for you, you'll hate the bike and never use it. Hopefully, in return for their time and effort with you, you'll buy a bike from Trek, or from whatever Local Bike Shop you visit for a bike fit session. if not, you'll at least be a little wiser as to what you need to fit your body.
WTB: Used Women's Road/Hybrid Bike... and some guidance
I'm totally new to the sport, and am excited to get started. I'm a student who just landed a grant for this summer, and decided this will be my big present to myself. I know I will need more than just the bike, but I guess it's a good place to start. My budget is somewhere between 300 and 400. From some research, it seems like I'll need a frame somewhere between 50 and 52 centimeters. Help a sista out!
I cannot agree more about the fit being the most important thing when buying a bike. DEFINITELY go to a shop and find a pro who knows how to fit someone for a bike. Riding a bike which is too big or small for you is not enjoyable (some people do it and don't mind, but then actually get on a bike that fits them and are like "WOW!" I was one of these people)
Are you going to be using the bike for commuting, recreational rides, or training/exercise?
On a budget of $300-400 dollars, you can get a decent bike. My low-end Raleigh Detour (a mountain hybrid) was something like $330 on sale, normally $360 or something. For reference's sake, I bought the bike in 2009. Prices actually might be lower given the economy.
And I third the suggestion about the fit. The mechanic at Trek was really nice to me despite my low-tech bike and the changes made a world of difference.
Trek in Shadyside also probably stocks a reasonable selection of Kona commuter bikes. I got mine there (a Smoker 2-9) last year for under $350 with a rear rack. Comes complete with fenders, too!
You should also check out Thick Bikes in the South Side, as they have a nice selection of bikes, including some used models.
REI has it's new 2010 Novara Buzz V out, I have the '09, and that rig is comparable to the Kona Smoke. Comes with allen bolt skewers and seatpost, too. Aside from the fenders.
A bike that doesn't fit and is below market price is not a good deal.
Don't make the mistake of settling for a bike that doesn't fit, if you don't know what frame geometry suits you best you may have a hard time buying a bike that fits as everyone states their sizes differently, and none of them quote the most crucial top tube measurement in their numbers. Any extra money spent on a bike from a shop that fits will be more than made up for in comfortable miles in the saddle.