For twenty bucks, I'd buy it and make it a pocket piece. If it's at least silver, you really can't go wrong.
The OP's coin looks OK to me, it probably spent some time under the sea (shipwreck). I assume that the OP's coin is an Ebay sale as he mentions feedback, and if so, it will sell for much more than $20. I have a similar cleaned pillar dollar from 1748. Spanish America 8 Reales 1748 - Mexico Mint
I would like to take a closer look to the rim. There are no bargains out there...so https://www.cointalk.com/threads/8-reales-spanish-empire-and-peninsulars-for-all.258294/