Sorry, but those "bumps all in the field on the other side" are a surefire indication that this coin is actually a modern reproduction. These fakes are made by machine, like "normal" modern coins, while the original cash coins were cast in sand. The bumps are the manufaturer attempting to replicate the bumpy, sandy background of a genuine coin.
The emperor being imitated in this case is Kang Xi.
Despite being fake, genuine cash coins of this very long-lived emperor are very cheap and common so the price difference between fake and real is very low. The "Chinese cash coins $2 each" trays that most of the coin dealers have around here usually contain many objects like this.
Don't say "infinitely" when you mean "very"; otherwise, you'll have no word left when you want to talk about something really infinite. - C. S. Lewis