A big reason I started dressing more like Fairy-Kei style is where to get clothes! It's so much easier :D
1) Well this isn't one store, but flee markets in general and second hand stores! I started going to flea markets only a year ago, and I found out that I had missed a lot! maybe you don't find something wearable right away, but you kind find textiles to sew with, and that's a good start.
2) I have always, even before J-fashion came into my life, loved H&M! of cource it depends on the seasons if you can find pastels, but often in the DIVIDED section I can find a lot, and of course in the childrens apartment :D
3) Ebay is again not only one store, but it's great to find good deals there!
4) A lot of stuff I bought at Bodyline for Lolita still works nice in Fairy-kei such as stockings, bloomers, short skirts ect.
5) Dream V Rakuten is also one of my favorites, even though I haven't beem shopping there jet, but I will! I love their shoes, and cute cut sews :D