If you want a cheap reflex that's suitable on a 22, Gander Mountain sells the Sightmark 4 reticle reflex sight for about 70 dollars. I had one on my 617 and the reticle image was VERY crisp. However, on my 610 it wouldn't hold zero, so I can't recomend it for anything with more recoil that a 22.
I've now replaced that Sightmark with a J Point reflex in a direct mount. The dot is NOT as sharp or distinct as that on the much cheaper Sightmark, partially due to the J Point only featuring 4 automatically selected illuminition levels as opposed to the 9 or 10 presets on the Sightmark. Also the J Point features an acrylic lens in order to shave a bit of weight instead of a glass lens like that on the Sightmark.
However, one feature of the J Point that makes it a hands down winner for me is that it's only offset from the bore axis by about 0.9 inch. Currently I have J Points on my 617, 620, and 610 and all 3 guns will shoot within one inch of the dot from 20 feet out to at least 130 feet. That's something that I couldn't do with any rail mounted sight that I tried. The converging sight line relative to the bore axis made the guns quite sensitive to distance. Set the sight for 100 feet and they would shoot between 3 and 4 inches low at 25 feet. Sight them closer and they would shoot high at long range.
As for the slight fuzzy dot, I'll admit that I would like a sharper dot to shoot with. However, it's certainly good enough to do what I want to do. I've managed a 1.75 inch group at 35 yards with the 620, and IMO for me to group any tighter at this distance would require using a handgun scope with 2 to 3X magnification.
Bottomline, if your only shooting at one distance, a cheap reflex such as that Sightmark will work quite well. However, if you shoot at a variety of distances, a sight with a large offset from the barrel will start to drive you bug eyed nuts.
When that happens, you might want to look at the J Point. While it's not perfect, it's the best shooting all around reflex I've tried even if the dot is a bit fuzzy in some lighting conditions.
BTW, if you didn't see my report, here's the link. Scroll down a bit and you'll find pics of the way the J Point can be easily fitted to a standard holster.
http://smith-wessonforum.com/lounge/155300-purchased-2-more-j-point-reflex-sights-range-report.html