Bare root trees are still available from my favourite supplier,
https://www.blackmoor.co.uk/apple-trees-eating-c1 but at around £30-40 for 2 year-old trees, they aren't cheap, I know.
People on my old allotment site, often took a chance on the supermarket trees, and most were happy with them eventually, but not all were the variety they were supposed to be, plus they are only small and whippy when they are sold, so do take longer to start fruiting.
So that's the choice, can you afford older trees or does your budget only allow for the supermarket varieties. How about 1 or 2 good trees for this year and then fill in with cheaper ones next?