If it is avaliable. I used to take a regular cardbord box anf then fill it with shipping shrink wrap.  Even at 10 yards it would not pass thru.  Not waterproof but all I had to do was replace the box when it got wore out.

Ya I use the shrink rap right now it works great, just looking for a few other idea that are a little more permanent.

I stuffed a feedsack with old clothes and rags.  Works like a charm.  Just make sure to remove all buttons and zippers.

I'm sure metal buttons could do some damage!

I guess it isn't exactly home-made, but years ago I called a company that makes shipping crates and packaging materials for where I worked. I noticed the containers that they made for us had that same kind of plastic like foam in locations that is in targets you buy. So I had them make me a 4'x4' backstop out of it for my backyard, and is three layers of I guess 1 and a half inch(?) foam glued together.  That was like ten plus years ago and I still have it, but now starting to show it's age some, ha!

My friend goes to a feed store and bought bales of hay that works good too.

I like to use pages from coloring books, and magazines tacked to it as spots to shoot at.

We have a place local that sells accoustic tiles for drop ceilings.  My friends and I went by and got a 4 x4 styrofoam block that they make the tiles from.  They have been shot for years and are doing fine.

I took a cardboard box and stuffed it full with old phone books and then filled in the gaps with tightly packed plastic shopping bags. Works like a charm! I also stuff old feed sacks with other old feed sacks and plastic bags, just be sure to get them packed in super tight!

I've made a target with a bunch of strips of cardboard sinched between 2 peices of all thread with a 2x4 on top and bottom. The strips were about 4 feet long by 10 inches wide. Stack the strips on top of eachother and put a 2x4 piece of wood on each side to keep the nuts from pulling through. The hardest part is drilling 2 holes through each piece of cardboard. After getting enough strips stacked on top of each other sinch it down tight between the wood.After that I made a stand out of some old c channel I had laying around.

I left it out in the rain a while back and it didn't last too much longer than that.

The easiest way to make a target is to take packing plastic and stuff it inside a burlap sack.

My bow shoots pretty fast so I have a store bought target now to keep from losing any arrows.

Spray foam works pretty good for field points...

Also heard of someione using old carpet pieces and bolting them together and putting inside a box frame.