Would just plain muslin work? I'm hoping for something as inexpensive as possible....

Definitely!

Sure it would. No one is going to see it once it's up on the wall.

Yup. Anything goes for a backing on a wall hanging. I even found some pieces of ugly pre-quilted material and am in the process of using up that hideous bit on a UFO. No need to add additional batting, as it is stiff enough as is.

Oh good - thanks! I was afraid maybe it wasn't good, that it would sag or something. :)

anything works because no one will see the back of it.

I almost always use muslin unless it's a gift for somebody else. On the special keepsake wall hangings I made for my sister in laws I used a large scale print that complimented the front.

That's what I use. I also use it when I'm making a practice block. I finish it then put it up on the wall.

Dingle, I LOVE your boxer!!! :D

I almost always use muslin for wall hangings. Cheap muslin, at that.

That's probably what I'll do then.

I always use muslin. Nobody will see it.

I try to use leftovers from the front of the quilt for the backing. If you have some leftover, I would try to do at least a border using it on backing so that the muslin does not show when the wallhanging is hung.

I use muslin a lot for this and it works very well :D:D:D

Yes, I used to use muslin all the time for backings.