REI has men’s Under Armour Base 2.0/3.0/4.0 undergarments for 75% off.
Examples:
UA Base 2.0 Leggings $13.73
UA Base 2.0 Crew $13.73
The reviews say these run slightly small so if you are between sizes go larger.
REI 100% Satisfaction Guarantee. Free shipping on orders >$50.