How do I get the shop to refresh? And how often does it refresh? Currently I have 7 out of 10 slots open with purchasable items, 3 of the slots are locked and don't have any merchandise. I bought out everything but the first 3 items, and got a message saying I needed to spend 1200gp? to refresh the shop, but I've done that and still can't figure out how to get the shop to refresh. Is it a timer based thing? Or is there some other, more consistent and quicker way to get the shop to refresh. I'd like to buy up as much Mii headgear as possible.
From this GameFaq's question, it sounds like the shop should refresh after a Classic Mode run or after a certain number of battles are fought.
I just bought some items from the shop and ran through classic mode. It seems that one of the "sold out" slots has been repopulated with a new item. I'm not sure if it was only one that refreshed because I did Classic on the easiest setting to run it through quickly? But I'd say that your best bet is to just fight more battles and maybe do some Classic runs and give it time.
I'm pretty sure its time based because I quickly ran through classic mode and nothing refreshed. in order to unlock all 10 slots you have to just spend a bunch of coins. My guess is each individual slot has its own refresh rate rather than the entire shop because when you go back only one or two new items are in the shop.