You might try looking at ULINE. I have a sealer I got for cheap but haven't tried it/ bought bags yet; was looking at ULINE last year and the prices seemed pretty good at high quantity. They have a warehouse near Trexlertown so if you are local you can pickup free there (not you sneaky but possibly others).
Dunham Sporting Goods has Weston brand. I bought the rolls. 3 pack of 11x18 for 17.99. $4 cheaper than Food Saver brand, which was 21.99 for a 2 pack. Plus they had a 15% coupon at the counter. Cost me $16 and change.