It also depends on whether or not you farm the manyu dailys.
I personally don't farm Manyu dailys, the RNG and rewards are not worth it to be honest, so I never run out of gold.

Also depends on how many rainbows/golds you are leveling. Rainbows are a bit more expensive to level than golds. (level slower, higher evolution cost.)

It also depends on your luck and if you are whaling or not...

If your luck is shit and you have only got 3*/4* the only Girls you have to Level are the Event Girls.
If you are a Whale you always have to Level Rainbows Units (and that's really expensive).

I would like to know how much Gold Moarsi has atm ...5 Gold???