BudsGunShop.com - Magazine

I suggest calling Taurus and asking them Customer Care Call Center
Call: (800) 327-3776 Monday thru Friday* – 8:00 AM to 8:00 PM (EST)

Domenico, GunsAmerica has factory new for $39----------------gunsamerica.com/908837504/Taurus-PT58-series-380-ACP-Fitted-12-round-Magazines-for-PT58S-PT58HC-Pistols-New-Unissued-but-Modified-Partial-Refinish.htm
The used 10 rounders on ebay and pre owned shelves in the gun stores have been listed for over $100

Domenico, I would check the for sale sections at some large gun sites like (6)un (8)roker as discontinued and hard to find firearms and accessories are often listed for sale by private individuals and small shops. Just replace the (6) & (8) with G & B.