I have seen Trijicon and Meprolight make them.

Does anyone know of a place to buy them at a good price?

And which ones are better?

I have seen some with the same color on all dots, and some with a different color front post.

Thanks for the input!

Both are very good, If you can find the Meprolight version with the 4 dot peep sight ( not the rifle sights with the notch)they are very good. I prefer them over the Trijicon.
Although, I have several set of Trijicon on my AR's. I have some with different colored dots, but like the standard green ones the best(Trijicon CP25)
You can buy the from donnie @ [url]www.sableco.net[/url]
Can't remember the price, but they are around $70.00 a set.

I just got a set of Trijicon's from C4iGrant on the EE.

Can't remember what I paid but it was reasonable, and Grant is a great guy to deal with. Honest, fast shipping, good prices, what's not to like?

Here's a link to him..........
[url]http://www.ar15.com/forums/topic.html?b=7&f=23&t=166974[/url]