I buy all my makeup from department stores or Sephora, MAC etc for several reason such as quality etc but mainly because i can try on a lip color or an eyeshadow there and then rather then the hassle of guesswork and returns/exchanges. As far as brands go, I don't limit myself to a certain brand however, my favs ARE MAC, NARS and BOBBY Brown. I feel that they cater to us south Asian skin tones more so then say Estee Lauder (just an example, nothing against them).
I have a shopping addiction so I spend alot of $$$ on makeup, clothes, bags and shoes and everything pretty ;)
I buy make up from Mac and Bobby Brown, only because of quality, its a bit pricey but worth it ( i think) I also spend loads on face creams, my fave at the moment is Elizabeth Arden. What i dont spend a lot on is nail varnish, in fact i dont even have any! but will only get a colour if im attending a very special function.