I did the spray-tan-in-a-booth thing once. It looked great but I hated the process. Being suddenly blasted with that cold spray took my breath away and made me gasp, which you're not supposed to do--breathe, that is! Being instructed not to breathe made me feel anxious and made me wonder a bit about the safety. It was expensive for my budget, too, something like $60 for two visits? Again, it looked great, but I don't think I'd do it again. Why not just use a little sunless tanning lotion on your legs? Also, some products are made with weaker formulations for body or face so that you gradually build up a "tan". I've used various kinds of sunless tan lotions for years and love them!
P.S.- I wish we could just be happy with our skin color as it is! I've heard in some cultures pale is considered more attractive and women try to lighten their skin the way we try to tan! It's silly that we're all out here around the globe feeling badly because of our skin. If only we could embrace our natural beauty!