It cost £6.99 for a 1m roll. There are other lengths, colours and thicknesses available.
I decided to make myself a little phone cable holder as I'm forever dropping the cable on the floor when not in use.
To do so I cut a small rectangle of Mayka, and chose one of my favourite LEGO minifigures - Harley Quinn. The hands on the minifigures are perfect for holding small cables like those for the iPhone. You then simply peel the backing off the Mayka tape and press it onto the desired surface. As long as your surfaces are clean and dry you can remove and reuse the tape so don't worry too much if it's not straight the first time. Then I put the cable in Harley's hand and pressed the back of her legs onto the Mayka to fix her.
Overall I'm impressed with Mayka. I'm sure it has lots of possibilities which I look forward to exploring and I love the fact its not permanent