First look at the price for buying 7,500 energy. Alright 19.95 bucks alright cool. BUT WAIT. Why buy that when you can just scroll dat mouse of yours and buy 7,500 ce WITH all of those cool stuff, and at what cost? Yep 19.95
Probably time to do something about that.
This sometimes happens, both in Spiral Knights and in real life. A sale causes the relative prices of two products to go out of order.
Note well, however, that you can purchase the starter pack only once (per account?). So, if you've already bought it and you want to spend another $20, then you're stuck buying the other thing.