An unwelded A2 would be at 15K or more, depending on configuration. There's many fewer m16a2's in the registry as opposed to m16a1's/m16's/RR's/etc.
Colt m16A2 - 15k or more
Colt m16A1-m16 - 12.5K or more
forged small hold registered receiver (like a Sendra and some Olympic Arms)
- 9K to 11K
forged large hole registered receiver (such as an SP1 lower)
- 9K to 11K
quality reweld (like a Norell or Stemple)
- 8K to 10K
cast registered receiver (like an Essential Arms)
-8K to 10K
If you really want a reweld just make sure it's a good one. As far as burst, you'll only find that in some of the m16a2's. If you do happen to get one with burst, it's no big deal you can change out the fire control parts.
If I were you'd I'd post a "wanted to buy" on Sturmgewehr.com, and maybe even one on subguns.com. It's free on Sturmgewehr and an ad costs $5 on subguns. If you post a WTB ad, you should get a fair amount of replies. Don't be in a huge hurry, the m16 market has been stagnant for a while. Of course the introduction of some new whiz bang, everyone's gotta have it upper could change that. I'd keep posting an wait for the right deal to come along.
You should also consider this when evaluating price. If you buy a gun in state you'll be paying one $200 transfer fee. If you buy one out of state there will be two $200 transfer fee's providing the gun is out of state on a form 4. If it's out of state on a form 3, the gun will transfer tax free to your instate dealer. If two $200 fee's are due (such as if you're buying from an out of state non dealer), you can sometimes negotiate with the seller and get him to pay one of the two fee's. And last but not least, sales tax may also be charged on an in state purchase.
let me know if you have any other questions...