I just cannot justify a $600 red dot scope on my ar, I am not somewhere where I need 50,000 hours of battery life or it to be waterproof 10,000 leagues under the sea. I want something like the Leupold CQB or burris vari x. I would rather not spend that kind of cash however.
Anyone know of or use a cheaper scope? 
What do you consider ācheapā?
Are you looking for a red dot/holographic sight or a scope?
What is your intended use for this rifle?
Intended use is target shooting. My ideal scope would be the burris xtr 1-4. I am trying to stay under $500 as I do not need anything special. I just do not want a scope that will fall apart after 100 rounds down range. I really like the idea of an illuminated reticule also. Some I have looked at are the bushnell that looks like an ACOG, and a NC Star, but they seem cheaply made.
Not much help, but if I was using an AP M4, about the only thing Iād swap it for is an AP T1. Anything else, Iād be going way up in price, not down. Sorry.
Well, if your rifle is not going to be seeing a lot of heavy use, and will be primarily for plinking at the range, you might want to consider the Millett DMS-1. Itās a 1-4X with an illuminated reticle. They can be had for $199 or so. Add in another 100-200 for a quality mount, and youāll be well under budget.
Hereās a 9 page thread to read through:
If itās primarily daytime use, the Leupold MarkAR might be worth a look, as would the Leatherwood and similar ones - Iād see whatās at SWFA as far as low powered budget variables.
Eotech 512 for $399.00
I know you said optic but sounds like good old iron sights will fit the bill and be a better investment than a cheap red dot.
This.
Well, I got something today, not what I expected. I went to Sportco and they had a burris xtr with rings and a fast fire on sale for $699 with 5% off. I about fainted when I saw it, and I even though it says it is the 1st gen, it had the red reticule and not the yellow.
These are on ebay for around $990. Even though I had to come up with about $150 more from what I sold the aimpoint for, I am very happy. However the fast fire is mounted very high and seems kind of useless. It would serve better mounted at about 2 Oāclock.
then now you just need the SAR from TNVCā¦
So the burris scope is fine, however the fast fire is broken and will not adjust. 