Since I go to yoga class 4-5 times a week, I invested in Lululemon and Zobha capris. They really make a difference. I used to wear ordinary black leggings lang kaso they were too sheer for the yoga asanas. Kapag nag-downward facing dog ako, wala na, kita na yung butt ko. Yung mga capris from Sasa naman chafe sa inner thighs and the waistband will roll down during some poses. Since Lululemon and Zobha specialize in yoga wear, their capris and leggings do not chafe the skin, are stretchy enough for more challenging poses, and are able to wick the sweat off the body.
For the tops, I wear lang sports bras and dri-fit tops from Old Navy, etc. I used to wear ordinary cotton t-shirts, kaso since I sweat a lot (yung tipong pwede nang pigain yung shirt after yoga), the t-shirts tend to smell and become heavy due to the sweat. So dri-fits tops talaga are the way to go.
If you intend to do yoga 3 or more times a week and you really intend it to be part of your lifestyle, I suggest investing in yoga active wear. Pero if you're just trying it out muna, ordinary exercise clothes will do.