I got a Sherpa on sale from BaxterBoo dot com. Bama loves to hang out in it during the day, especially to chew on her antlers.
At petco today I noticed they have a smaller Sherpa for $40 that's made exclusively for them. It's not as long as the other ones, but it still looks comfy.
Some airlines have their own preferred carriers. Sherpa makes some of them I think. Southwest has one they sell which I have debated getting...since Bama loves to hang out in hers (and since her first one, a non Sherpa) didn't last as long as we hoped, it wouldn't hurt for us to have a spare.
Marshall's, home goods, tj maxx are good stores to find pet products, although you never know what you will find. I've lucked out at Tuesday Morning and found piddle pads at half the price I usually pay. ;-)