for a while ColorCore stock (HDPE plastic for signs) is available at CICWorkshop’s site. Today I compared prices from where I got it before (Amazon) and Ryan Drapela offers the stock fopr roughly half the price! I make all the signs in my offices and around my house from that.
(I do not have any connection to CICworkshop, except that I just LOVE! that shop, that family, the team there, their stock and tools and sets etc they offer, and Ryan publishes the best videos with tons of tricks of the trade, how to make things, and also how to develop a store: he built his from zero to 7 figures within some years)