Here are 3 different flavors of "Sonic Crisps". While sometimes a potato chip is called a potato crisp in the UK area, these appear to be 3D puffy crispy...somethings. But! They are shaped like Sonic's head, which is a plus. The magazine describes the flavors as 'mouth stripping' though reports are, that they are made of corn, and were enjoyable.
When you could find them at the grocery, they were 6 packs for 89P which is described as a bargain at the time.