Well that's kind of an interesting dilema. We don't know what kind of shooting you'll be doing, and you don't know what kind of scope you'll need.
Do you want cool, functional, rational, or a good combo of all three? We can give you recommendations all week long, right? But really, you won't know what really trips your trigger til you get an idea of what suits you best for your comfort, preference, and needs, right?
Here's my thought on the deal: Everybody ought to have a decent .22lr rifle- they're just fun and cheap to shoot. Ok, with that in mind, it'll eventually want to wear a scope too. Now, scopes are neat (especially with the likes of .22's and .223's) in that they are not a use once and throw away kinda deal. Why not go with a 3-9 or 4-12 Mueller, Konus, or other relatively fine crosshaired sporting scope that'll set you back $100 or less? You can have a basis for learning your own way around the world of optics, scopes, dots, etc. If you don't like the way the scope behaves on the AR, move it to the .22, trade it in at SWFA.com, either way- it's an investment and you'll be building your own knowledge based on your needs.
A red dot, will have very low magnification. A little light inside the body shines a dot, crosshair, or some design onto an inner lense and you sight it in the same as a scope. They tend to be great for larger targets and non-precise type shooting much beyond 100yds (in my opinion).
Hollowgraphs are a little rectangular body with an upright lense (like a screen) onto which the little light is shown onto. Again, great for tactical and relatively close shooting. No magnification that I am aware of. And again, not much good for precise target work beyond 100yds (in my opinion).
I live out in West Texas and shoot high power rifle, coyotes, and prairied dogs- my idea of percision and accurate shooting is to hit little things as far as my ctg, rifle, and personal abilities will allow. So, my idea of what a AR or any rifle needs my not gee-haw with yours at all. That's why I rambled on the way I did in the start of my post. I think it's much better all the way around for you to learn what suits you best instead of 20-100 guys telling you what you need. Do you really want to end up spending your wad on a purchase and always wonder, "Hmm, is this the best choice I could have made?" Nothing is wrong with cheap when you're still in your learning mode.
