This roll of 3M electrical tape is supercheap on Amazon right now

It's just black electrical tape, but it's made by 3M and a roll costs just [amazon_link asins='B00EZPZ9CK' template='PriceLink' store='boingboing' marketplace='US' link_id='251d24a2-ccb0-435d-ade7-cb22648a2749'] on Amazon. It's temporarily out of stock but you can still buy it at this price and you'll get it when Amazon gets more.