Bushnell TRS25. Which i just got it for my Arsenal AK. Its about $85 with free shipping from Amazon.
For under $100 I have to agree. Really you should kick in a little more because most optics in this price range are junk. I have two Trash-25s from the local Cabelas for $80 each. Picked one up and liked it so next time it went on sale I got the other. Surprisingly few complaints in over a year.
Anyway, this is the only place I cheaped out on my ARs and so far I've gotten away with it. Definitely wouldn't stand up like an Aimpoint Micro but so far so good.
The biggest issue with assembling an AR isn't so much getting the parts together right - it's getting the right parts together.
US Army 1966-69, VFW Life Member, Retired Geek
Before i got that Bushnell.. i bought the UAG 4 reticles red dot from Amazon. Its damn cheap for $30. I wanted just a simple inexpensive red dot for my AK. I already got Eotech for my DD.. my main rifle. Cheap stuff doesnt lie.. the UAG elevation/ windage couldnt be adjusted. Hate to admit i loved the simple not bulky design. So i returned and got a refund. Finally bought the Bushnell with good reviews and not bad for design. And so far im happy with it.