I've heard amazing praise for Amazon Essentials Line of clothing and right now they are running a huge sale for men and women! I just snagged these 100% cotton tanks 2 for $9.50 (tons of colors):
https://www.amazon.com/Amazon-Essent...=ATVPDKIKX0DER

Lots of other deals: https://www.amazon.com/deal/8433160a...RnOAWPoNQHA25w