Where can you buy new door panels for a 1990 Chevy Beretta Indy?
New!? Ouch. Good luck!
Map pocket and lower panel are no longer available.
Armrest is currently selling for $63.25 each side.
Door panel is selling for a whopping $300 each side.
Looks like its time for you to make friends with the guy at your local junkyard, or ask someone on the bstuff.com forum. Even used ones in good condition are extremely rare.
You can, however, swap both door panels with the 91+ style. Dashboard must be swapped as well if you do this, as the new panels are wider. These are more readily available used. (New prices are also going for ~$290 each).