http://www.reapermini.com/ spend $35 - free shipping (US) plus they have build your own sets and some great paints
amazon sometimes - keep an eye out for sales and if you have prime, it's even better
http://www.warcolours.com/index.php?route=product/category&path=59 - cheap paints, I like their metallics, and most of their one coats (I find the black is glossy though,
ymmv) shipping is not bad, especially from Poland
rosemary&co - I found their brushes are great and shipping is not bad at all
secret weapon minis - I like their weathering powders, though they have expanded and also they have a lot of basing supplies
http://www.waylandgames.co.uk/138-paints-modelling - even though it's shipping from
UK, it can be worth it, depending what you're looking for
http://www.miniaturemarket.com/ - they have a reward points program and often put stuff on clearance that can make it worthwhile throwing in a few paints to go with as well
basing type materials, I'll also check out scenic express
Anyway hope that helps some