No offense to anyone but try your best not to buy anything at Walmart , they are a bad , bad chain. I posted in a reply about the tactics used by Walmart , they deserve to go right out of business ASAP !
That being said a used pair of 60/40 BDU's will run you about $20 , cheaper than anything youll find in one of those fancy outdoors clothing places and much longer lasting. Ive had my 60/40's for going on four years now , use them hunting or fishing or 4 wheeling , working concrete , light construction , etc and they are still in great shape.