(OOC: I've seen rules for camel costs in several places. The most expensive I've ever seen is the one in Sandstorm, which is 100 GP. I'd go with that as a rule of thumb since it's WotC. Also, even with combat training using Handle Animal, the camel really sucks compared to a horse (one attack as a secondary weapon--yuck!) which is part of the gamist reason for pricing (I've seen horses outperform level 1 PCs in fights). If you prefer simulationist, well-bred horses were more prized and expensive than camels back in the day anyway.)