Anyone who has one of these firearms knows how hard they can be to find for under $50. Currently 30rd mags are on sale for 32.99 (reg 44.99) with 2nd day FEDEX and no tax.
The discount won't show until you add to your cart. Also it says 1-2 weeks but I just ordered some yesterday and got the shipping confirm.
https://bt-parts.com/bt-30183-magazine-30rds-complete/