Checking the reviews this one looks like the best loo roll stand under £20 on Amazon.
2 in 1 space saving design: 4 toilet paper rolls on saver, 1 on holder
Steady design: heavy base
Chrome plated steel - mould and rust resistant
Toilet roll holder with swivel top: smart and convenient
Freestanding - could be conveniently placed
If you don't have prime, add something for £3 and you'll have free delivery. This toilet paper for example: https://www.amazon.co.uk/Tork-110316-toilet-compatible-conventional/dp/B000MQHNDY/