I do realise that this has absolutely NOTHING to do with renewable energy, but I would hope that each and every one of us would appreciate a tip here and there on where to save a little cash....

Last weekend I decided I needed a push mower to supplement the riding lawnmower. So a-browsing the garage sales I go.
Didn't see anything worthwhile, so I decided to stop and see my wife at work at WalMart. As I'm walking in I notice they have a Weedeater brand 22" lawnmower for $99.00

I figured if the thing only lasted one season I could always use the engine on the gokart I'm building for my son.
I have to say I'm pleasantly surprised. They are finally catching on to an idea I've had for years : instead of using the smallest engine possible and revving the nuts off it to cut the grass, they've gone the opposite route and stuck a Briggs & Stratton 4.5hp Industrial / Commercial engine on a 22" mower deck and set the governer to half throttle it. What this achieves is a VERY quiet gas powered mower that has NO trouble getting through anything you throw in its path.

Those thistles are 3.5 to 4 feet high!! And I've already chewed through an almost 30 X 20 foot swath of them!!
It does a very nice job on the lawn, too. Quite the manicured look to it from such an inexpensive mower. I mainly bought it for getting in and around the trees in the front yard where there's just not enough room to get the 42" riding mower in. But I'm finding this push mower does such a nice job that I'm mowing much more than just the tight spaces with it.
Now, for $100 you can't expect Toro or Snapper quality here. They've skimped in a few places (plastic cable ties to hold the throttle and blade brake cables, plastic wheels that look and feel flimsy, etc), but they've put quality in where it's needed. The deck is AT LEAST 16 gauge if not 14 gauge. It's pretty hefty for such a small mower. The handle is steel, not aluminum, so you can flip this thing around and the handle doesn't bend or yaw. It's EXTREMELY easy to start. My 12 year old son (a self proclaimed wimp) can start it one handed. It is so basic there are only two controls - the blade brake and the pull start. There's no throttle at all. It's preset. You push the primer bulb three times, give it one yank and it's running.
So far I've used about 1/2 a gallon of gas, and I've had it running under some pretty strenuous conditions for about 3 hours right now. Which falls into about the same as the last mower I had which was straining its poor little 2.5hp guts out just trying to mow a "normal" yard. This thing is plowing through shoulder-high weeds, chopping up 1/4 inch thick thistle stems, and just in general accepting out and out abuse and still going strong.
So for those that are looking at a replacement (or first) mower and don't feel like spending the outrageous prices Sears are asking for thier one-season-wonders, I can heartily recommend this little puppy. And coming from someone that used to repair and service lawn mowers for a living, I consider that pretty high praise......