Look on Ebay - there's typically plenty of 2-9.9hp old 2-strokes that need some work.
Bear in mind though, if it's a non-runner due to simple things, just needs a carb clean, set of gaskets, new plugs, etc. fine, it might be an easy/cheap repair. But if you need to start pulling the entire powerhead apart, maybe dealing with some seized bolts, and/or having to replace many mechanical or electrical/ignition components, the parts costs very quickly add up, could easily overtake the initial purchase cost, and you're unlikely to recoup it should you want to sell on after the project finishes.
If cost is no object and you just want the learning experience and a fun little project, fine. But just be aware that depending on what condition the engine is in, it can get expensive.