triathlon beginners guide
Budget advice
Visit/Join a Tri Club and check out what second-hand bikes the members are selling. Aim for the low end, say less than $1000. Make sure you ride a few different bikes so that you can compare.


It needs to be comfortable and fit well.
It must have quick-release wheels. 


Also, work out what shoes and pedals you are comfortable using: will you use toe clips or clipless?

Serious Advice
Find a local Tri shop or LBS and talk it over with them. Be firm about your budget, and that it includes clothes, shoes, and pedals. A good shop will let you ride the bike before you buy, provide some free service and fit the bike to you. Shop around as well. Be up front with the staff: tell them that you are starting and are checking out your options.

Good luck!