Here is a "coin" being sold on eBay that is actually NOT;
Here is the object itself.
The seller is new to eBay. But he describes the object as if it was a 1772 Madrid 8R made of silver which is obviously incorrect. He gives a weight of 28 grams.
In the field behind the King's portrait is a raised feature:
That is rather clear with a date of 2002 - it is some sort of copy.
If you notice the object clearly is surrounded by a metal ring that is connected to the edge of the object. I presume it is a cast that includes the rim as an integral part of the object.
For that reason I believe it is a "Bowl Bottom" similar to the example illustrated on page 174 of my book. For over 100 years such faux coins have been mounted as bottoms of bowls, cups and ash trays. They are curios no more no less. It is not a coin.
It was made in 2002 not 1772. It is not even silver - looks like electroplated brass or bronze.
In the old days, this would have been removed from eBay - but not because it is illegal. It is only improperly described.
However, a value of $ 99 or anything near that is ABSURD. Perhaps $5 would be more realistic.