I kinda feel the RP shop is incomplete . Most other games advertise a "pay more to get more" theme.
Now i know this is a game for kids, but I'm sure there are people who spend a lot of money on this game.
Wouldn't it be better to support those kind of customers by adding some % bonus for each RP pack? As things are now , there's no incentive to buy 100$ pack over 20 times 5$ .
I'd suggest adding some bonus to the purchase :
1750 for 15$
3000 for 25$
6000 for 50$
I feel like this would not break the economy ,and would rewards those high spending players.