Coinbase has changed the way they transact and its costing people a fortune.
In order to make crypto easier to track by the tax department, they now put your sale through as a cash advance, which means with pretty much all banks you will be whacked with a ten dollar fee, as well as likely being charged an extremely high percentage of interest on those transactions (usually whether its been or month or not, just like a cash advance from a credit card)
I have noticed that when I use my mastercard or visa DEBIT card not credit card I avoid the extra fees. It still goes through as a cash advance though.
Tl:dr dont use your credit card on crypto exchanges. Get a debit card 
Tried and tested multiple times now. No fee but if i use the cc definatelt a fee. Mongrels