When buying thru audiogon how do you protect yourself ?

There are indeed third party "escrow" services, which will provide a level of safety for both parties. The two most established internet escrow companies are at:
Tradenable.com
Escrow.com

Know who you're buying from. Check any feedback they have on any site that has feedback.

E-mail them through A'goN and ask to talk with they,..that you are interested in what they have for sale. If they don't want to speak with you...don't buy from them.

And, as always, if it sounds to be good to be true($-wise) it likely is.

Get a home phone # , address & call them & get a good idea if they are trustworthy. back off if anything AT ALL rattkes you concerning their character

I will not buy by prepaying with money order, unless the buyer has a lot of positive feedback. If the seller has one feedback or none, don't take the chance.

Personally, I have sold items asking for prepayment, and have been lucky enough to get buyers who will do so. This resulted in a number of positive feedbacks, which over time has given me a good rating, which I believe makes a big difference to the buyer. It certainly does for me.

I have not used Paypal, etc., but have read some negative experiences people have had, such as phony checks being accepted, or ruined equipment being returned. Hence, I would want more information on such services before using them.

COD is safer; however, you don't know what is in the box until you open it!