Zhanchi vs Guhong: is a matter of preference, personally I like the Guhong, try looking for comparisons of them online.
White vs Black: I have a white cube and I wish I had black, white after a while looks really dirty. Also white stickers on white cube look kinda weird so some people put black stickers instead of white.
Stickerless vs stickered: Stickerless cubes are illegal in competitions, but are much better for carrying around/putting them in your pocket, you don't have to worry about the stickers at all.
Try fasttech.com, they have really really cheap cubes with free shipping worldwide. The main downside is that the shipping times take long (sometimes a month) from what I've heard, never tried ordering from them but many people from the forum did.