Where to find bike in MTL

Hi, I'm new to Triathlon (but have been doing many sports, including soccer, track, swimming and spinning). I don't own a race bike and as a poor student I really can only afford 500$(can). I am very serious about raceing and plan to do compete every year. I was wondering were can I find a decent road bike (that I will only use for racing, not commuting...I have a bike for that) in Montreal for around $500 new or second hand. People tell me that if I want anything good I need to spend at lease $900, but I simply cannot afford this and I am not ready to take out loan just to buy a bike. Over $500 is just NOT an option (maybe 600 at the most, but that's REALLY pushing it). There must be a way to for me to race on a non steal bike (Aluminum would be ideal, all carbon may be wishful thinking!!). I already looked over crags list and kijiji, but they are all way over priced. If you know anyone who is upgrading to a new bike and want to sell their old one, or any bike stores that will build a decent race worthy bike for my budget please, please please let me know. Being new to this I don't were to start looking.