I've been leveling and evolving girls quite a bit the past week, not to mention upgrading some equipment, so I got pretty strapped for gold.
Luckily, I was about to level today, and my stamina was nearly maxed, so I grabbed a coin boost and did 8 Coin Rush runs for ~30k at 80 stamina each, so I'll at least have enough to evolve 1-2 more girls should the need arise.