For those rare occassions when i do use brushes, i use artist's brushes from my local art store. they are stiffer than most which i find better for lining with and they are a lot cheaper!
i hate using brushes, but when i do, i'm using FL!RT brushes (from kohl's, the flirt line is made by estee lauder which is mac's parent company so the quality in their tools are pretty similar only flirt is like 1/3-1/2 the price of mac!) and avon ones ('m not sure the prices on those though, my mama got them for me
agree with everyone above. japonesque is not really much cheaper than mac. essence of beauty is a very good, comparable d/s brand. i get all my syntehtic brushes from the craft store. michael's has weekly coupons too.