Dick's right, you can do it your own way not terribly expensively yourself, if you don't care for Jerry's effort.
Patches like the one Dick described are probably $2-3 a patch if you order 100. Simple text stitching on one bag is probably $10-25, depending on whom you approach to do it.
I'd guess there is some small chance the bag company might not require all the same bag, but that complicates things a lot for everyone, and after doing the t shirts, I know how easy it is for things to spiral out of control.
(In case anyone is wondering about the golf shirt orders I asked about last year, I had a rather large personal life change immediately after I posted the offer, and that put things on hold. However, if you did place an order, you can expect a free golf shirt to be arriving sometime this fall.)