@news For me as monthly subscriber from Europe the prorated subscription price for my upgrade to Premium was a bad surprise.

My bank account is maintained in Euro. My bank charges a fee of min. 1.50 Euro for every ​non-Euro transaction.

1.50 Euro for the monthly subscription​ of $5 (or 4.51 Euro) is hard. But 1.50 Euro for the prorated $1,44...

I try to mitigate this by changing the card, but this is an adventure of it's own.​