I have some grateful dead t shirts from their concerts in like 70's 80's do they have any value ?
I'd try eBay. People sell all kinds of weird things on there, & I know there are plenty of Dead Heads who would love to buy them! Price may be low, however, but you never know!
probly depending on the condition and its market value, look it up and see.
probably not much $
Wait alittle longger then search on inernet they probly arnt cus its just 30 40 years old