I’ve printed kilos and kilos of Geeetech PLA, and that’s some of the cheapest on AliExpress (although I used to get it directly from their website before I realised doing that was normally more expensive). It arrives wet, but other than that, there’s (nearly) nothing to complain about (although years ago, I had a roll with two lumps of grit in it that caused clogs). I’ve had mixed success with their other materials - their ABS+ started burning in the nozzle while still being cold enough that layer adhesion was bad and their high-speed PLA has ridiculous oozing that causes ridiculous stringing, but their PETG and TPU seem fine. I’m pretty confident that their basic materials are absolutely worth £7/kg.