Does anyone have any recs for some inexpensive ceiling soundproofing material?

You mean other than rolls or batts of insulation?

Not sure what you are asking here.

well, I suppose you could use standard fiberglass insulation, as you would in the walls of the house, which would help reduce noise in the supper level somewhat, but don't they make various products designed specifically for sound dampening?

There are several materials and sources out there. Insulation is helpful, but not very helpful per lab data.

• Look at decoupled framing (room within a room)
  
• Lots of mass (double 5/8" drywall... forget MLV)
  
• Absorption (R13 in walls, R19 in the ceiling)
  
• Damping. This is one of a number of damping compounds on the market. They are used in between sheets of standard drywall.

There are many articles available online as well.

Yes they do but they are not inexpensive.

http://www.cinemashop.com/3/sound-isolation.htm

http://www.audimutesoundproofing.com...ning-room.aspx

http://www.acousticalsurfaces.com/

For an inexpensive solution that has lab-tested value:

Starting from bare joists, install R19 fiberglass. Standard thermal insulation. Don't waste cash on insulation marketed as "acoustic." Can be paper faced or unfaced.

Then install wood or 25 ga. metal furring perpendicular to the joists, every 24".

Attach double layers of 5/8" drywall to the furring, not the joists.

I've heard of people stuffing their walls and ceilings with styrofoam egg cartons which apparently works well for sound proofing a room.

That's a common urban legend

I'd put a layer of rubber down between the ceiling and the foam panels or egg cartons.

That's another urban legend. Egg foam, egg cartons, eggs, chickens are all ineffective at stopping sound.

Foam can reduce the echo from the low-energy sound that remains IN the room, however will do nothing to keep the high energy sound from leaving the room