Hey TX! I just did my first sprint two weekends ago. First off, go join "SlowTwitch", as it's essentially a site dedicated to the triathlete. Huge source of info and the participants are ridiculously helpful. For a first sprint, you'll find that the bike ride is typically around the 9-mile mark, at least in California sprints where I'm at. I'd say about 30% of the participants at the sprint I went to were riding every-day type cruisers, mountain bikes, and such. Half were riding a variety of road bikes of all sorts. I rode a racy geometry road bike with aero extensions. The consideration is that if you buy a road bike and then subsequently get crazy about competing, you'll find your self wanting to move to a dedicated TT bike. I already have that tri bug and bought a TT frame just today! So,can you borrow a bike or get a quality road bike on the cheap? Just about any roadie will serve you well.