Hello William ---
It's a Mexican 8 reales from the Guanajuato mint (the Go mint mark) with assayer initials PF. My 2015 copy of the Standard Catalog shows the following values:
F12 - $27.50
VF20 - $33
XF40 - $60
MS60 - $290
Based on that, I'd assign a 2015 catalog value of $30 US dollars to your coin, probably closer to $50 today (compared to 2015). But catalog values are very rough guides, not guaranteed price levels.
To demonstrate the vast range of values in collector coins, I have included two pictures from recent auctions by Heritage and Stacks Bowers (very reputable auctioneers). The first coin, with gray background, sold for $65. The second coin, in the NGC slab, sold for $150.
Further, the one at this eBay page:
sold for $75.
All in all, I'd say a collector would probably pay between $50 and $75 for your coin. A coin dealer would probably offer you $25 for it.
PS: Don't use eBay prices for guidance UNLESS they are for completed, "sold" auctions.