If you are on a budget and can't decide, there is always ebay. It's hard to find something you need at a price worth the cons of ebay shopping, but if you have an entire range of possibilities you should at least check it out.
Got to say so far my experience of ebay in 40k has been pretty good. Most of my orks and nids came off ebay.
I used to get most of my stuff from Ebay. In my old age I've gotten sick of the ol' green stuff bath and toothbrush dance. Very messy and time consuming.
Check out another crappy 40K blog here: www.keepcalmandescapefromreality.blogspot.com