TSO should really lower the price of endless copper mine by alot since 100 euro's is way way to much money to pay for one building.
to get 20k gems from weekly and level up u need 200 weeks if u only get gems that way since 200x100 is 20k or if u get to level 50 u get a total of 7350 gems and that is far from 20k
but taking into consideration how long it takes to get lvl 50 u might get around 5000 gems from weekly login