eBay is a place where people sell stuff.
- Often it is where dealers and merchants advertise their day-to-day merchandise. eBay is how they advertise.
- You might get a really good deal from a guy like any one of us who is reselling an extra part or piece. Someone who isn't trying to squeeze the last penny out of the sale but doesn't need it anymore.
- You might get a worthless and unreliable counterfeit part made by a sweatshop in another country.
- Or, you might get true New Old Stock parts that have been warehoused for decades and are being sold off one at a time by someone who is in the business of selling old stuff. The risk of course is that old parts do deteriorate over time, natural rubber is one thing that doesn't have an indefinite shelf life.
That is the beauty and the risk of ebay. Welcome to the hobby!