Ok so I just gave jewel Farm a try and I dont really get it. I only had 71 coins.
I flipped 1 card for 50c and quit jewel farm. I received my prize in my backpack. So that all went well.
Now I want to refresh..but when I click 'free refresh' it says you don't have enough coins. Which is right cause I only have 21 coins left. But I thought you could refresh for free after 5 min? I've already waited for about 10 min.