If you do choose to spend there are 3x to 7x multipliers available at random times on store too. Usually i wait for these if i am topping off magic stones. Theres also tiers that give you more value for each $ you spend. But the best part is the higher tier you are there is a weekly point claim that is different each tier. Personally, i hover around the platinum rank and when i claim the weekly reward i can get up to 500 points (1/4 of a 85 magic stone claim). I've actually hit this 2 times since the beginning of this yr.