It does work like this. Remember that I said that the credit card was exhausted? This is a sort of pre-paid credit card. To put some credit in there, I need to go to the bank and put in at least a min. amount of money
In Greece many players used to buy with paysafe card (prepaid card- you can buy it even from small shops).
It's 5$ for about 50T, which can make your life easy (if you are careful of course in auctions)

but is it enough to have one GK playing all games? ,, i guess he will be too tired
I use only one GK and some times in games I don't care much, a low quality 0T academy.
A free agent 3* veteran with 1T also could be useful for some non important games.