I have one of the official Playbill frames (for my Nathan signed Producers Playbill). But if you're looking for cheaper frames - I suggest a trip to IKEA. They have these frames which come in packs of 4. They are basically pieces of 7 x 9.5" glass with cardboard backing and then a clip goes on each side. It's not actually closed in, so not the best for archiving, but they look nice when hung on the wall.
I have mine (all 10 of them, sad I know...) hanging on the wall as you go down to the basement, so they're hidden from the sun and everything.
~Jessica
"If you start from a place of joy and charm, you can get away with a lot in the second act. It may be that that's my life. I'm not sure."
~Roger Bart