I'm buying one of those with 25,000 miles on it for $525. The transmission pictured has 4.44 gears, meaning you will also need to find a rear differential with 4.44 gears, preferably one that was set up like that from the factory (auto Outback LTD, Legacy GTLTD, Forester S, 2000-2001 2.5rs). I found a 2001 2.5RS diff for $150 with 84k. With labor from a good shop, I'm looking at around $1500 back on the road.
Be very sure you want 4.44 gears. Your car will be much quicker but it will suck gas like a funny car. I have a 1 (one) mile commute to work, and we have a 4 cyl minivan for shuttling the kids, so I'm not sweating it.
joeaxial did the responsible thing and put 4.11's in his.
I'm off to the junkyards right now to check out the diff and the tranny.
www.car-part.com is a great parts locator. I found my stuff within an hour of my zip code.