Like anything else, there are various grades and prices for gaff tape. I've used "Pro-Gaf", "Permacell" and "3M" all quite a bit. The 3M stuff tends to run toward the premium end of the price scale. $14/roll for a single roll of Pro Gaff at your local theater supply house is about right, you can find it mail order on the net for as low as $7 or $8 (plus shipping) if you want to buy a full case. Just Google for "gaff tape". Ask the drama teacher at the high school where they get their supplies, even if they don't actually use gaff tape (we didn't in HS, too expensive), the same place they get lighting gel should have it.
It's the only thing I will let people apply to my carpet, or my cables. Duct tape on cables is a bigger no-no than duct tape on an FRC bot
You might want to try
Full Compass in Middleton. Their prices on gaff tape are pretty good. I'm not sure if they actually have a storefront location, but if not they are so close to you that shipping should not be too brutal.
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