The men's shirts that I bought for my husband and teenage sons shrunk the worst. They were the men's Gildan heavy cotton shirts from jiffyshirt. I was pretty frustrated b/c apparently you can't return or exchange shirts that have been washed...pretty convenient for them since there's no way of knowing if they will shrink unless you wash them!
BUT, to be honest, they are the cheapest shirts and biggest variety in color I can find, so I'll probably buy more, just get much larger shirts than I need so that when they shrink they will fit!

The quality/thickness seems good and I'm making a lot of them for our trip, so I can't pay 5-8$ a shirt somewhere else!