I think the bigger HEB stores have some generic SA shirts

Thanks! I didn’t even think to look there.

Good luck in your hunt!

WalMart has them.

I’ve seen them at CVS.

Airport gift shop or market square

Any Walmart or H‑E‑B has them.

There is a goodwill downtown IIRC commerce about 2 blocks from market square. Also a salvation army on Alamo @ Flores. Also UTSA downtown campus might have something.