BlackxWhite Lolita is hard to pull off (but hey, I still do it) you just have to make sure it's not over the top and packed with frills.
Lolita is an EXPENSIVE hobby unless you are a master seamstress. Some of the top quality items can be $200+ and beyond for one dress.
Gothic Lolita doesn't have to be black, it can be wine red, chocolate colours too.
A good place for beginners is
BODYLINE YOKOSO! but don't rely on it to create your whole wardrobe. The quality varies a lot.
Shoes don't have to be big heeled, mary janes work fine too.