A boy buys a video cassette player with a remote control at a jumble sale, or car boot sale. It was described as being made from a "spongy" material, and was possibly green (and maybe pink, although I'm less sure on that). I remember the sponginess specifically, because I thought he should have realised it wasn't normal at that point!
Later, he was watching something when his mum (I think) walked in front of it and he paused her by mistake. I think he could play/pause/fast-forward and rewind her. I think he then took the remote control out and about (possibly to school).
I'd have read this between 2000 and 2004. I think it was either a short standalone book, or a 'chapter' in a compendium of children's fantasy/sci-fi stories. Aimed I would guess at 8-12 year olds. It might have included pictures. If it did, they were typical children's book black and white line drawings, slightly cartoony.