You have a limited time and daily store but why not combine both in to a full featured store with rotating deals that includes tabs for
Upgrade, Full builds, Tokens, Specials .. etc. etc. It would help those who ether just miss an offer, TLC or one of the "events" get the option to buy what they need at the moment.
Maybe you could also add a "Sell" feature where players can get rid of stuff they don't need at a suitable 'coin' credit value offer; even if well below the value it is if you wanted to buy it. The coin's could even be locked for use only in the store.