Here is a t-shirt I just came up with, produced and sold by a vendor on Etsy (I get no money from it). It's 2-sided, so you can be a human billboard. 😉 (Or you could order it special with one side.)
#TaxTheRich
https://virgodesignboutique.etsy.com/listing/4355602806/tax-the-rich-shirt-protest-tee