I made the switch from cups to bags for rooting cuttings this year and found 3x8 inch bags at staples.com with free delivery to your local store, 1000 for only $7.79. They are a little flimsy at 1.5 mil thick, but have 2 mil if you want to be a big spender at $14.69. This is quite a bit cheaper than ULINE's $23 + shipping for the S-1331's. It's a little late for this season, but keep it in mind for next year. No, I do not work for Staples. I couldn't figure out how to insert a hyperlink, so here it is in all it's gory detail:
http://t.staples.com/Clear-Lay-Flat-Poly-Bags-1-5-mil-3x8/product_939455

Figured I would give them a try.  When I went to order the 2 mil bags they showed $14.69 but when I added them to my cart they went down to $10.72.  I just placed the order with free shipping to my local Staples.   Thanks.

Good price thanks