How many coins cost to unlock bulding terrains?

18/03/16 10:00
The first are 10 coins, how many coins for the rest?
18/03/16 10:22
It is rising continually (10 then 20, 30,40 ... Until you unlocked the last one)
18/03/16 11:12
Best to use money untill you only have a few left to get because when you use gold balls it increases the price of the next slot but using money to upgrade wont increase the gold needed for the next one