I have to say I own a lot of Mac brushes and now have quite a few Sigma brushes and I love them just the same! SIGMA BRUSHES :: Dupe List for Mac Brushes. I have a bunch of both, and it is true, they ARE great dupes.
I cannot rave about Elf products enough. By far the cheapest makeup, but it's seriously all high quality, gorgeous, and long-lasting. These are some of their most popular products. My fave out of the bunch is the eyebrow kit.