It really will depend on which Adobe product or suite you are trying to install. In general though most of our Creative Suite 6 products require 10.6.8. Which Adobe product did you purchase? Besides your operating system is there other system requirements which you also are not currently able to fulfill?
Apple sells OSX upgrades via the app store and in their stores. Unless your hardware is realyl that old and wouldn't support 10.6, i see no reason why you couldn't spoendf those 29 bucks, if you realyl wanna use CS6.....