If you can get a real bargain... nothing's wrong with Ebay... for something like a (good) starter, bid 5 bucks, you never knoww when luck turns your way...
On the other hand... Bill's right... Ebay is not the right place to get stuff when you "need" it.... there is always good stuff on Ebay... but NEVER when you need it...lol... So don't bid too high.

Now about your engines... when you get the starter, be careful when you hit your tiny engine with that big starter... it is not very difficult to break or bend something in your engine... ask me how I know ...

Hand starting these tiny things can be a PITA... but it is not difficult... just hang in there you'll get the hang of it sooner or later.
Prime (but not too much), glow power on, test flip... see how it does... nothing yet? Try a little more prime, and give it a second try... it is just a matter of finding the right combination.

On small engines it can also help to wash the engine out with fresh fuel before trying to start it. Castor becomes a thick goo over time that will cause so much drag in the engine it will never start...