The cheapest I have found (last year) can be found here :
http://www.sedistribution.com/store/catalog/Clearance-Sale-p-1-c-283.html OR
http://www.grabbagswimwear.com/catalog/
http://www.srsport.com These guys have the Speedo Flipturn suits that I think are nifty for around $30
The grab bag suits are the ones where you send them the size and quantity and they will send you discontinued or overstocked colors and/or designs. You do not have a choice regarding color or style. Keep in mind that for the males, almost everyone wears the Jammers now (knee length), rather than the Speedo racers.
My advise is to wear a practice suit to practice and your team suit to swim meets- your team suits (ie a little more expensive) will last a little longer.
Any questions, let me know. If you do a google search, just do Grab Bag Swimsuits.
Also, if you have families that are close to you, it may be worth your while to get together and do an order, that way, everyone can save on the shipping costs.
**On another note, the polyester suits will tend to last slightly longer, although they are a little more expensive. If you order a polyester suit, I recommend going 1 suit size up.
When a suit fades, (ie elastic wears out)- DON'T THROW IT OUT! You can wear 2-3 suits at a time to make the most use of it. People around the pool can testify that there are usually at least 2 suits on me at all times!
Keep in mind, that all of the sites will offer better deals throughout the year. Search for a while, see what you can find. If you get something outstanding, let me know and I'll pass it on!
Hope that helps- happy shopping!