What type of power steering fluid does the 2000 chevy blazer use?

There's no magic here; Your 2000 Chevrolet Blazer is just going to use Your standard synthetic transmission fluid. You can pick up a quart of a generic store brand for around $7, and for a couple bucks more, get a Valvoline brand of full synthetic. Just to note, yes, You use ATF in Your power steering; lubricant is lubricant here. Topping off or flushing and using clean fluid will correct a lot of steering issues, so for the cost, it's worth doing the preventive maintenance here.