Shammy is always awesome.
If you're looking for discounted rates I have three sites to recommend.
1. Cheap caribbean dot com
2. price-travel dot com
3. bookit dot com
Price travel is an online agency located in Mexico, so sometimes they can offer the rates that are usually reserved for Mexican nationals. So sometimes, you can get a really good deal. I do most of my travel through cheap caribbean because it is usually the best rate.