unbalanced Gold earnings

It is so hard to get gold coins in this game. You may lose more gold than what you can get back from. Although I have found a way to get easy gold and save up. I sell stuff for 1k gold coins and only spend 300= at max. It's slow money making but it should do since there isn't a faster way to get more gold faster. Plus the upgrades are expensive which is why saving your gold will be tough.