Okay, so it's not "treatment", per se. But I have this large 6-ft tall bifolding wooden frame wrapped in fabric with a couple layers of cotton batting inside. I tossed a wool blanket, bundle of silk cloth, and a wool poncho over it, then faced my microphone away from it. Then I recorded an alto saxophone.
I didn't know this would work this well! I guess all the layers absorb a lot of the sound that would be hitting the bare wall- then reversing against the parallel bare wall on the other side of the room. I have some nice plans for VERY inexpensive panels functioning on this same method. What kinds of stuff have you guys seen/come up with for inexpensive, aesthetically pleasing sound dampening/absorption?
 
(I'm still a victim to some bad echoey stuff in the corner of my room... I think I'll hang some curtains up there to help dampen those.)

Just having carpet and furniture in a room changes the acoustics so if something home made works like you need.... that's all that matters.   The home made stuff was all the early recording studio's had. It's better than nothing.
 
All I use is the carpet, and furniture in the room..... Seems to work OK for me too.

My tracking room is a small sunroom (porch turned into a spare room) that is heavily curtained (this is Texas, after all) on the two sides that are windows.  About 10 x 8 ft.  It isn't totally dry, since there is a wood wardrobe against one of the solid walls and the last is sheetrock over what was the brick exterior.  Plus, one of the curtained walls is fronted by shoes and shoe boxes - the wife's.  It isn't totally dead and ideal for electric guitar.  I use a cheap ribbon backed off the center of the cab with the other half of the fig 8 pattern about the same distance to the wood door so it picks up some brighter sound.  I also just recorded a trombone - it sounded killer too.  I usually do vocals in a bigger, "liver" room where I mix.
 
As guitar says, anything, even a drying rack can help tame reflections and echoes.  For most modern recordings a drier sound is better - not dull but dry.  You can put ambience back on, but it is hard to get rid of that small, empty room ready-to-be-painted echo/reverb.  Dry that up.  As long as it is not a booth, it is hard to make a room dull for electric instruments.  Vocals and acoustic instruments do need a little "space" or they can sound unnatural.

Most recordings I've made in my carpeted furniture filled studio have been pretty good.If I want some ambience I simply throw open a door that leads to a hallway...So if you're asking what I've actually done to my space acoustically...that would be pretty much nothing as I haven't seen a great need for it.You might remember I mentioned before that I also have a  closet with a curtain front filled with "stuff" that can absorb sound. This works as a baffle and a darned good one.
 
I have pics of me online somewhere building bass traps but I haven't used them much. Not everyone can get away with that, but my space seems to be pretty neutral, at least in the lower mid to high frequency ranges. I do educated approximations on my low bass *ahem* and I can get fairly close....close enough that you might not know it.
 
I haven't recorded sax either... no two cases are exactly the same. Sounds like you found a good solution to your problem Dave.

I have had curtains nailed to the wall  every x feet for the longest time - nothing recognized for its sound treatment virtues, mind you - I only wanted to make the place a bit darker, and got the idea after visiting a couple of funeral homes.
 
But when I started installing proper room treatment and took them off, I realized just how much they even out the high frequencies in this room.
 
No way I'm taking them off - I installed the foams on top of them.
 
Whatever works... 

Rain
I have had curtains nailed to the wall ...... got the idea after visiting a couple of funeral homes.

 
Now that's funny right there......

Hah Rain, I like that idea! But my mother wouldn't go for it in her house, too bad. I'm cooking up some other solutions that are similar- I'm thinking through attaching a curtain rod on the wall opposite the bifold and hanging a curtain/blanket/rug from that, so perhaps similar....

Guitarhacker
Just having carpet and furniture in a room changes the acoustics so if something home made works like you need.... that's all that matters.  

So does the carpet match the drapes? 

Jablowmi19

Guitarhacker
Just having carpet and furniture in a room changes the acoustics so if something home made works like you need.... that's all that matters.  

So does the carpet match the drapes? 

OK, so that WAS funny Mr. 19.

Sometimes there is no carpet.