12 pages of discussion = lots of great links to products and to homemade ideas too.
I took a PVC pipe and hung from it - a tarp, and a blanket (two layers since I found out the hard way that even a good tarp, single layer, you can hit right through it).
Eyebolts, nuts, clamps for the blanket, a couple carabiners, and a bunch of clothesline and it hoists up to the ceiling when not in use (just roll the tarp up and tie it to the pipe). $25 max. and you're in business.
let the bottom stay loose (the 'loose' bit is how it's enabled to gently catch the ball - but you need to see if you have place for a full swing. I can't hit wedges with this setup - too steep. And woods, it's a bit tight.
The cheap little mat at the store lasted quite a lot, until the wife started then she started hitting the corners and tearing it up.
I have a Monster Turf product coming in a day or two. (http://www.allturfmats.com/product-p/mt4860.htm) that link takes me to a page that's cheaper than anything else on that particular product - don't know why. Will update once I get it to see if it's any good.
If your swing is decent, don't worry much about the edges. If not, just get a bigger tarp and bring the corners forward - you hook a carabiner and line to a corner and tie it off to keep the corners forward.