If you're willing then send that back as your counter-offer.  

He called me after the deadline and counter offered 600,000 while leaving me all the inclusions in the house such as a 1,200 bottle wine collection and all the furniture in the house but, instead of 550 he wanted 600k.

We got a counter offer back this afternoon, which we have accepted!

They made a counter offer.  

This is the theoretical maximum you can pay and NOT leave any of your money in the deal after refinancing.This is NOT a requirement to do a deal, however what is acceptable to leave in will be different for everyone depending on your own cash flow and financial ability.Starting MAO – Get this number by subtracting another 15% from your MAO.This is a decent starting point to begin your negotiations.If you get no counter offers at starting MAO, you will need to increase your initial offer.Market conditions will always impact starting MAO.

It was here where I started to learn from counteroffers and negotiations.

Just recently this property has been reduced to 17995, I have never received a counter offer, so when you low ball on a property, how do you know the realtor isn't saying in his mind they will never accept, or I'm not going to waste my time.

$20k on a $500k house is well within a reasonable counter-offer or appraisal spread.

I submit something around 93k and they turn around with a counter offer for 94k and I'm shocked and excited.

You counter offer could limit the down side saying at the contract price or no more than 5% (whatever) less, at the appraised value in the event the appraisal is less than the contract price.In so doing you could also ask that the sale price would be at the appraised value, not less than XXXXX dollars.