i suppose i can still put an optic on the A2. I want to keep the price low also, just over $400 for the parts kit

You *WILL* regret it later. I and everyone else I know with an A2 came to this conclusion. Take the extra time to save up and buy a detachable carry handle. Heck, you can find chopped carry handles on the EE for <$50.

You will be forever thankful for the flexibility. Trust me, I'm a college kid and have *NO* money; I would still save up to have the A3.

Once you're adjusted to them, you'll wonder why anything else was ever designed...

/S2

I go a step further and have a picatinny rail gas block on my uppers. (All Armalite M15a4 uppers). If I want a A2-style front sight, I just slap it on there. If I don't, no problem, I can take it off. Granted, that's not as much of an issue as is the carry-handle, but it adds flexibility.

With rails, you can always add on. With standard A2 carry handle/FSB, you better like what you have.

A3 for the versatility in optics mounting options. Because once you go optics you will probably never go back to irons for primary use.

If you have any intention of mounting an optic, the A3 is worth it for the flexibility.  However, I would caution against buying a rifle with an eye on the bottom line, instead of what you want.  For example, changing the A2 to an A3 later will cost more in money and time than buying A3 now.

If you want the A3, save for it.

Well, you do give the ability to use the carry handle to carry your AR like a purse

Hmmm....  Here's my take on this:  About the only thing I can think of is weight (if you are an "ounce Nazi").  A flat-top plus carry handle is heavier than an A2 upper by a handful of ounces...and an A2 upper is heavier than an A1 by about the same (I know there is a post by me around here somewhere that lists the relative weights of Bushmaster upper receivers...).   So, if you are the type that wants to build a super-light basic carbine (A1 upper, BM superlite barrel, 6-pos stock, and forget about all the "H-buffers, fancy grips, dreaded double heat shields (too much weight., right? ), etc.,) then a flat-top may not be for you.  But, if it's your ONLY rifle, you may get the dreaded "flat-top" envy from time to time at the range...or if you hang out here "too much."    That said, if weight really does concern you, rest assured that the "extra" weight of a flat-top with carry handle or optics is usually centered on the receiver and it doesn't effect handling much.

All this aside, I have my 14.5" flat-top + BUIS/M2, 93A stock & Colt M4 handguards...as well as my FF 17.5" flat-top + Leupy "SPR-ish thingy", and now...yes...I am looking to build a K.I.S.S. A1 uppered AR-15 with a 14.5" barrel & RRA 6-pos stock for a light & fun little plinker.

YMMV.

I'll add my $.02 to say I purposely choose an A2 upper for one of my builds because I wanted at least 1 KISS rifle. I hate optics mounted on A2's so I figured it would be a good way to make sure I kept this rifle simple. The only other possible reason I can think of to use an A2 upper would be to build a rifle\carbine as cheaply as possible.

That said, I still think the A3 is the way to go and my decision to use an A2 upper was foolish.