I recently purchased a Walther PK380 and love taking it to the range. It only came with one magazine and the range where I bought it rarely if ever gets them in. Ditto with the next 15 gun/sporting goods shops I checked in my area (St. Louis) as well as online. Any suggestions on sellers where I could get an extra mag or two?
Gunbroker has one. Not cheap, but maybe check back and someone will post more. Standard caveats of eBay apply.
Midway has them on backorder. Midway is a good company to buy from.
You’re not going to find any unless you get lucky with a private sale (or win the Gunbroker one), they’ve been in high demand and have been on factory backorder for a while. Personally I’d just order them from Walther America / S&W customer service and wait.
Also might try Brownells.