Fun! Well, since I found my yellow ATG at a thrift store for $3.00 and bought 6 rolls of each 1/4" and 1/2" wide tape (both fit in the ATG) off ebay. I don't think my cost savings factors into the retail pricing of your charts.
I still haven't used the rolls up yet. I do like that the Tombow tape isn't too expensive for how little I use in feet of tape. If I'm doing a big project I'll pull out the big gun.