Seeing the Kathmandu Thermaplus base layers are quite popular, I thought I'd post this deal from Wiggle, both mens and womens are $13.60 plus postage. Free postage for orders over $80.
The fabric is close to the Kathmandu's Ultracore (moisture wicking, high stretch, double knit, silver salt to inhibit bacteria/fungus growth) which sells at 2 for $70 at Kathmandu. Makes this a bargain IMO.
Deal link is to mens. Womens link here.
Don't forget 2.8% cashback via Cashrewards!
I have the short sleeved version. I am very happy with it.