Right now I MIGHT pay attention to the store once a week, sometimes I forget to. There's nothing to remind you, and no habit forming "check the daily deals" incentive to check. The only reason you could want players to only open the store once a week, is not wanting them to spend TP's because you're allergic to money
Brick and mortar shops need longer sale windows, lead time for news print/TV ads, word of mouth etc.
MMO's don't have the same problems a B&M store has. I'm going to guess the average active player logs into the game on an almost daily basis, and the consistent spenders, on a multiple hours per day basis. The DDO store then is kinda like a Wal-mart where a large number of regular shoppers come to the store EVERY DAY, but they don't buy things DON'T EVEN LOOK at the prices on stuff, they just chat with friends in the isles, watch the TV's, plays the Video Games, and then leave the store not having bought anything. If DDO was Wal-mart
For this reason the store should be put on a smaller more rapid time scale. Get those people checking actively, incentivize browsing in the store (through flash sales)
1. There should be "Daily Special" with no preview, every 24 hours.
2. There should be flash sales AKA "blue light specials" (with a better name of course) announced (not too spammy now!) in general/trade chat two or three times a days during peak hours. "there are three items in the store that are 30% off" for the next 3 hours" is going to make people look at the store, believe me...
3. There should also be the weekly specials. and typical seasonal deals you currently have.
4. there should be an additional type of daily deal that IS announced ahead of time at the beginning of the week 7 deals, intended to make you put a "mark on your calendar" to log on that day and get that Item (and perhaps others)
The main purpose being to encourage and get people in the habit of logging in to check even if they aren't playing the game a lot.
Right now you only have #3, and you used to have #4 but for some reason stopped doing it while I was gone. I have no idea why.
I have ~5000 tps to spend, and I like supporting the game, but I also like to get the most value I can and usually wait until a sale to buy something. Yet I know there's utterly no point in opening the store for the next week... So I wont, and this often leads to me forgetting to check the next week, because no routine behavior is being encouraged.
In Tribes: Ascend (A F2P shooter with a cash shop) I log in every day, even though I haven't played but once or twice this whole month... I log in to check the daily deal, which are not announced, occasionally I play a round or 7, I remember what a great game it is, and spend the next block of free time playing. Point being the store/daily specials can actually keep players connected to the game.