The wizarding family of Potters descends from the twelfth-century wizard Linfred of Stinchcombe, …whose nickname, ‘the Potterer’, became corrupted in time to ‘Potter’… His reputation as a well-meaning eccentric served Linfred well, for behind closed doors he was able to continue the series of experiments that laid the foundation of the Potter family’s fortune …as the originator of a number of remedies …including Skele-gro and Pepperup Potion. His sales of such cures to fellow witches and wizards enabled him to leave a significant pile of gold to each of his seven children upon his death.

So that’s how the Potter family initially get their wealth. Fanfiction writers often attribute it to ‘Sleekeazy’s Hair Potion’ which is also fact but more recent.

Linfred’s eldest son, Hardwin, married a beautiful young witch by the name of Iolanthe Peverell, who came from the village of Godric’s Hollow. She was the granddaughter of Ignotus Peverell.

Incidentally or otherwise knowing Rowling, Stinchcombe happens to lie ‘west of Dursley’.