head to your local supermarket and ask about getting a hold of a bale of compressed cardboard out of their box compactor.
ideally, get a "loose packed" bale, only ~50-75% compressed and, also ideally, one that contains only cardboard (i found an onion bag inside my last bale that snagged on my broadies).
buy a 300m roll of cling wrap and wrap the bale with multiple layers.
sit bale onto an old tyre for stability.
print out your favourite target face and tape to the bale. move the target face around a bit each time you go back to your range.
once you've shot out one face, turn it around and shoot the other side. once that's shot out, re-tie some string around the shot out faces and cut the string it was initially baled up with. two more faces to shoot.
when it's completely shot out, take to the tip then go back to the store for another one.
happy shootin.
note: you want to be shooting into the "open" faces where ther cardboard is stacked up, not into teh top or bottom where the cardboard lays across the face.
be warned: a cardboard target will blunten your broadies in record time.