I had one of these.
Commodore wasn’t much later. It had an optional tape drive.
I still have a vintage computer collection. Unfortunately our house was burglarized 6 months ago and much of it was taken. I don’t think I have any more Timex/Sinclair computers, but some of the accessories were left behind.
Most of the early home computers used cassette tapes for storage games and programs and ROM cartridges for games and programs. I doubt whether the thieves who broke into our house had any idea what they were actually taking, most of them were in the original packaging and looked like new. Occasionally old computers that are in good condition and have become hard to find or have an interesting history do sell for fairly impressive prices on eBay.
I borrowed one of those from a friend once just to play with and then went back to my blazing fast Commodore 128.