I have bought 4 bike short things:
- Bike underwear from MEC.ca for me to wear underneath any shorts or pants I have. I paid just about $20 for these. http://www.mec.ca/Products/product_d...=1117113188525
- Baggy shorts from MEC.ca that I paid about $40 for. Can't find the link from MEC.
- Cannondale baggy shorts from eBay. Paid $27 + shipping. I think these shorts were manufacturing defects. The back of the short rides down so I feel like a plumber. Still, they're cool shorts. http://cgi.ebay.ca/ws/eBayISAPI.dll?...tem=7153263363
- NEMA baggy shorts from eBay. Paid $34 + shipping. By far the best shorts of the lot although the inner lining is probably made for guys with skinny legs. I have to pull them up otherwise the chamois lies too low and it feels like I'm wearing diapers. Once I pull them up, they're good. http://cgi.ebay.ca/ws/eBayISAPI.dll?...MEWA%3AIT&rd=1
Overall, I think eBay is your best bet. The stuff in the local shops is way too expensive.
Edit:
And don't forget what the Underwear Nazi says. Underneath any of these bike-specific shorts, be they underwear with chamois, lycra with chamois or baggy with a chamois - do NOT wear your normal underwear.