--Go to your local thrift stores and find 4 used projection screens as in picture A. 
(Note:  The ones I found were only $5 and $7)

--Stop by the home improvement or hardware store and pick up the following pvc pipe and joints.

• 3/4 inch to 1/2 inch coupler (shown 1) -- you'll need 2
• 3/4 inch right angle joint (shown 2) -- you'll need 2
• 3/4 inch to 1/2 inch right angle 'T' corner joint (shown 3) -- you'll need 2
• 3/4 inch 'T' joint (shown 4) -- you'll need 2
• 3/4 inch thick-wall pipe (shown 5) -- you'll need 2 10-foot pieces

--First, remove the screens from the tripods along with any bracket which may be at the top of the extendable center post.  The tripod will look like picture B.

--Next, cut a 6-foot length from one 10-foot pvc pipe.  Then cut a 3-foot length.  Now cut the remaining 1-foot section in half.  Repeat this step with the remaining 10-foot pvc pipe.

--Screw the 3/4 inch to 1/2 inch couplers (shown 1) into the 3/4 inch to 1/2 inch right angle 'T' corner joint (shown 3).  Attach the two 6" pieces of pipe into the two coupler joints (shown 1).

--Attach the coupler, joint, and 6" pipe combinations to each end of a 6-foot pipe and slide it over the top of two of the tripods as shown in pictures C and D to create the front tier.

--Place the two 3/4 inch 'T' joints (shown 4) onto one end of each of the 3-foot pieces of pvc pipe.  Raise the two tripods for the back row to the 6-foot height and slide the 'T' joint over the adjustable post of each tripod as shown in picture E.

--Attach each 3-foot pipe to the empty socket of the 3/4 inch to 1/2 inch right angle 'T' corner joint (shown 3) in picture C.  This creates the two side walls for the stage, completing the bottom tier. 
(Note:  If the curtain needs to be raised, you do so by adjusting the center post of the front tripods and adding an equivalent length of pvc pipe to the bottom socket of the 'T' joint (shown 4) in picture E.)

-- Now, to complete the puppet stage frame, simply place one remaining 6 inch piece of pipe into each of 3/4 inch right angle joint (shown 2).  Place the right angle, 6 inch pipe combinations to each end of the remaining 6-foot pipe and slide it over the top of two of the tripods as shown in pictures F.

--That's it!

--Here are a few suggestions for easily adapting the puppet stage.

• To create a backdrop curtain, line all four tripods in a row, use the right angle joints on the two end tripods and use the 'T' joints on the center two tripods.

• To create an angled side wall, you can replace the corner coupler with a 'T' joint, then attach a 2 inch piece of pipe to the outside socket and add a 45 degree angle joint for the side pvc pipe.

• As for curtains, use a non-see-through material such as a heavy gabardine that will not wrinkle when packed.  It's usually better to use Velcro to create the pocket that the pipe will go through.  This will allow you to more easily set up the stage and position it before putting on the curtain.