For display, I like to go this route...
https://www.ebay.com/itm/8-9X11-5X5M...72.m2749.l2649
These are rigid sleeves, and they keep the Magazines/Programs from bending. Someone will inevitably chime in that these are not "safe" in some way/shape/form... but I have used them for decades and have suffered no ill effects whatsoever.
In order to display the Magazine or Program, I just prop the rigid plastic sleeve up on an easel. The easels are readily available at any craft store or on eBay/Amazon. There are dozens of styles available... 3 of which are as follows...
https://www.ebay.com/itm/5-SMALL-BLA...-5i:rk:33:pf:0
https://www.ebay.com/itm/Gibson-Wire...!-1:rk:43:pf:0
https://www.ebay.com/itm/Frosted-Hin...ss!98077!US!-1
I suppose you could use a mylar sleeve with acid-free cardboard backing to keep it rigid. That's probably what a museum conservator would suggest. But I like my way better.
Hope this helps!