Adobe stopped selling non-subscription versions of its software a while ago. You might instead be interested in Affinity Photo on the Mac App Store, which is a great Photoshop alternative at a fixed price. I switched to it because I don’t use Photoshop enough to justify the monthly price, and the huge amount of Creative Cloud background processes were annoying me and wasting my battery life.
Microsoft still sells Office on an up-front basis through their own online store and through retailers. But you will not receive an upgrade to the next version of Office when it comes, i.e. you’re buying Office 2016 only.
Beware of suspiciously cheap offers, especially on eBay. These aren’t legitimate no matter what the seller says. Now, you might not care about that (fair enough), but you may find that in a few months’ time it stops working and suddenly it’s less of a bargain than it seemed.