I just do a search on ebay using the words Merrick bully sticks. Here's an example of one.
100ct. Merrick 6" Bully Sticks from makers of Flossies - eBay (item 250484397510 end time Aug-24-09 12:33:42 PDT). There's a $10.00 fee for shipping anywhere in the states, so that's not a bad deal, but sometimes they ship for free. It really varies, and I just buy them when I can get them for around $2.00 a stick. There are also sold in smaller lots, but you pay more per stick. Since they last forever, buying in bulk works best for me.
Here's some other listings on ebay for them.
MERRICK BULLY STICKS, great deals on Pet Supplies, bully sticks on eBay!. I've bought from two different places, and have been happy with both.