For less than 20$ i get 40GB here in Denmark

EDIT: this one https://www.oister.dk/mobilabonnement/taletidsabonnementer/o... and then I took advantage of a "double your data" offering they had. It's 120DKK for 20GB, usually.

For 20$ I get unlimited everything in the UK

Most likely your speed will decrease to something like 128kbps after a cap.

That's true on every network except Three. Unlimited data on Three genuinely does mean unlimited without any restrictions (well, one actually, data used tethering your phone as a wifi hotspot isn't included). You could download a terabyte of stuff for £20/month (about $25).

I'm 15GBP/month with Three for unlimited data, 4GB tethering which is fine for the occasional train journey of email/twitter.

I have 12GB of tethering included in my £18/mo unlimited plan.

For $125/month I have 4 family members on an "unlimited data" plan from T-Mobile (really that's 13Gb regular data, unlimited Netflix and other streaming).

I did buy all the phones outright though, which was $2200 upfront.

Don't forget that wireless is a scarce resource. I know that current mobile plans could be improved a lot, and the tricks that were invented to dance around the Shannon Limit are amazing. However, those tricks only push back the inevitable: there just isn't enough bandwidth.

TMobile is excepting Pokemon Go from bandwidth metering