I mostly make my own VK stuff... Oh my... Let's see how much help I can be...
Although, I've been able to make outfits out of things I already have. I also pull inspiration from J-Rockers as well. It gives me better ideas about what works and what doesn't. Thrifting is good and altering is fun as well.
I sometimes shop on YesStyle too. I got my extra long cardigan from there really cheap. I've never come across anything really VK there but I look around and see what I can work with.
Livejournal sales posts are the best too! I bought a SEXPOT ReVeNgE shirt from someone on there for only $5. Which says a lot because SPR is really expensive. Hot Topic is a good place too but I've noticed that they are selling less and less "goth" stuff lately. I have to look online though, since I haven't for a while.
For accessories, I make my own for the most part. The only times I buy jewelry is if it's on sale. Things that can be used in Steampunk jewelry make for amazing VK accessories and Steampunk stuff is getting pretty cheap since it's getting popular.
Just play around with things. Alter things, hunt for things, and just have fun with it.
RadCon 2012: Cosplaying as Howl (Howl's Moving Castle)
SakuraCon 2012: Cosplaying as Syo Kurusu (Uta no Prince-sama), Duke Venomaina Gakupo (Vocaloid), Tsubasa Amaha (Starry Sky~In Winter), and Ruki [The Suicide Circus PV] (the GazettE)
Anime Expo 2012: Cosplaying as Kotetsu T. Kaburagi (Tiger and Bunny), Ruki [The Suicide Circus PV] (the GazettE), Duke Venomania Gakupo (Vocaloid), Howl (Howl's Moving Castle), and Shizuo Heiwajima (Durarara!!)