I have a new music player which requires Wi-Fi.  It will attach to my home router no problem, but won't connect to my iPhone's Wi-Fi hot-spot, no matter what I try.

As it happens I have a TP-Link 4G LTE laying around, which I presume I can use for the job.

Usage will mainly be while I'm on holiday, so I'll get off the plane and buy a Data SIM, stick it in the 4G LTE, and we're away, but I'd like to check it'll actually work first before I leave the UK.

So, I need to buy a Data SIM, as cheap as possible, no contract, just a SIM as cheap as I can find which will work, and I hardly need any data on it; just enough to check it'll work.

Any suggestions as to what to buy?

Many thanks.