I live in the city with a wetland behind my house (and a park behind that) and I don't dare shoot back there. Never have (well, i did when it was just a big corn field).

As far as your question goes. I have no idea either why that target costs so much. that huge block is the only really big one on the market that i know of. they need some competition for one thing.

the local outdoor range has 2straw bales stacked on top of each other. a piece of wood on top and one on bottom and then giant lag bolts (maybe not lag bolts, but you get the picture) that are bolted down putting extra pressure on the straw. so, you can just keep tightening up as needed. they are awesome!!!! If i lived in the country i would TOTALLY build one like that. couldn't cost more then $40