ASOS and Primark plain/cheap tees are awful, they're thin and partially see through!
I've got a few H&M organic cotton or something tees, they're nice IMO.
E.g. http://www2.hm.com/en_gb/productpage.0229656023.html
My grandad called t-shirts Sloppy Joes. Really don't know why, and it's a bit tricky to ask him now without the assistance of Psychic Sally.
£65 for a t-shirt.
Are you joking? £10 100% cotton is where its at.