I believe the cost of normals is between $20 and $40 now. Also depends on where you get them (always try for trusted breeders or specialty stores you KNOW are good and knowledgeable) and how old they are.

As far as keeping two, certainly not necessary. They aren't social at all, as was stated, and therefore don't get 'lonely' like so many other small animals. As long as you give them places to hide and low things to climb on (they are terrestrial after all) a single leo will be just fine. I've had my guy for well over 9 years, and rescued him as a juvi, so he's been quite happy all that time.