Savagewolf said:I would go check out your local bike shop. Ebay and other sources seem great, but you might want to really know what fits you best before you go and spend a wad of $$$.
Your L.B.S. and help you find an affordable bike to start off on. Once you start really getting into things, then you can do the upgrading.
Working with your L.B.S. also helps ensure you have a place to ask any questions you might have as well as help with any problems. Don't underestimate their help, especially with adjusting the bike to fit you and helping you choose the correct bike for your size.
just something to consider, but there are levels of bike "fit". When I purchased
my Trek 7100 from the LBS they give you a "general" bike fit (no more than similar advice I got on frame size from an onlike dealer) and they made sure that the seat was adjusted properly, again something that you can find on the web as well.
now if you are talking about the "bike fit" that goes along the lines of software to figure out whats your optimum position on the bike and seat angle
etc that usually costs extra. And its used for setting up a bike for use in time trials and triathlons... so again blanket statements about how the LBS will truly "fit" you to your bike have to be taken with a grain of salt...
there are also ways to make a "general" size bike fit you through changing some things on the bike (usually put on for free at a bike shop) but if you educate yourself you can do the same thing inexpensively.
for examle you can change stem height/length etc.
do a google for "sheldon brown" and he has articles on bike fit AND how to
change a bike to make it fit better through some inexpensive equipment changes.