My home altar is almost all stuff i've bought at thrift stores, garage sales, etc..it's pretty nice looking too given that. I don't know why, I feel like there's more meaning to it when I have to go find a home for Dharma stuff that's basically been abandoned, is hanging out a goodwill, and whatnot. Honestly to me that's what makes my altar have a life so to speak, it would be far less meaningful to me if i'd just ordered it all from some catalog.
Of course I know nothing about setting anything up institutionally, I only know on a personal level I do not consider "authenticity" to be limited to spending lots of money on products with some official stamp of approval.
Also on craigslist you can sometimes find stuff like Butsudans, statues etc. if you wanted to go that route, in many cases the previous owners will specify that the thing were used for Dharma practice.
"Just as a lotus does not grow out of a well-levelled soil but from the mire, in the same way the awakening mind
is not born in the hearts of disciples in whom the moisture of attachment has dried up. It grows instead in the hearts of ordinary sentient beings who possess in full the fetters of bondage." -Se Chilbu Choki Gyaltsen