Anyone who has put an FM relay on from a block or such remote site with no wifi, what is the easiest cheapest method of playing out the internet stream?
Laptop or Pi with 4G SIM modem etc
Or android phone
phone is cheaper but could lock up and need reboots, pain in the butt for someone to keep physically going there, right?

There are some solutions available at a price.....

One of the members on here has a really good system that uses a small single-board computer and a mobile phone modem. It "keeps itself alive" too, and includes a silence detector, obviating the need for revisits!

A Pi has got expensive these days, but yeah what a good solution

You can get away with the Pi Zero and a soundcard.

Your other options include a VHF or UHF link to the output site from somewhere that does have wi-fi: One station we did a few years ago used the wi-fi in a nearby coffee shop, with a cheap, junked "Netbook" for the logic and wi-fi reception, and a small link transmitter (about 200mW) on Band III (between the DAB multiplexes). At the transmitter site there was a simple crystal-controlled link receiver, and the main rig. It worked flawlessly for almost five years!