We can show you around if you like, provided it's a weekend. Shops are a bit difficult to pinpoint unless you know where they are.
There actually isn't all that much in DenDen Town volume-wise (in terms of cosplay anyway) ~ through the K-books and Lashingbang in the Melon Books building both have racks of used costumes and a few wigs/accessories on sale (unfortunately, at prices that make one hiss through one's teeth >.< ) Animate/ACOS has new Prichara wigs, goods and costumes. Geestore!
is tucked away on a back street and carries COSPA costume items, Tantrap bagged costumes and ocaisionally m.i.a. brand Touhou costumes. There is a Cospatio upstairs. Good luck affording anything there.
Mandarake in Amemura (near Umeda and Shinsaibashi) has the largest used costume and wig selection and the best selection of all the Mandarakes I've ever been to (Tokyo included). The prices are also a lot more reasonable on average. Nearby is Bodyline, with a VERY cheap cosplay shop on the 2nd floor, Prisila's HQ (wigs) and Lovepop Studio
(Alice Forest, Alice Garden wigs, Venus Eyes contacts). The Shinsaibashi shopping arcade is also GOLDEN for cheap dramatic shoes, socks/tights, underthings and crazy accessories.
has a wig shop in the Osaka ATC building and sponsors the most popular and populated cosplay events in the area. There's an event almost every weekend and the shop can only really be practically visited when attending (or wading through) ^^;
If you're willing to pay 450 yen and ride a train for 30 minutes, there's a secondary geek-town in Kobe (Sannomiya) with another Animate/ACOS sattelite shop, and another more reasonable Lashinbang with a smaller selection but better sales. If you're in the market for laid-back anime/manga shopping, I like the atmosphere of Kobe's geekland more than DenDen Town. There's less sprawl, but a lot less people to shove through and the atmosphere is pleasantly local in comparison. (there's a Yellow Submarine, 3 Animate shops, my favorite Toranoana, a Gamers, a Boys Love drama/game shop, a Lashinbang, a Melon Books, a few capsule markets, a game shop or two, several card shops, a maid/goth seamstress, some figure/retro toy stores, and a buttload of tiny hole-in-the-wall arcades etc.) If DenDen Town is Osaka's Akiba, Kobe is it's Nakano.