I once agreed a deal with a massive company, it was a big deal, for a big domain but I realised afterwards I left a lot of money on the table as it was in Escrow.
All that weekend, I was thinking of ways to get of the deal without losing the buyer, I come to the conclusion I couldn’t, I had to honour the price I said and put it down to experience.
If $50k was good for this seller, they should have stuck to it, not change their mind when the other party agreed just because “it was too easy” that is not the way to do business.
If you get as far as starting the transaction then I agree, you can't and shouldn't back out at that point. All is agreed and in motion.
This stuff about a verbal contract, unless it's clear that both parties have agreed to enter into a sale, clearly, then surely that's different.
For example if I have the following emails:
Buyer: How much for bob.com?
Seller: I'd want 50k
Buyer: Ok we'd like to purchase for that amount
Seller: Actually I don't want to sell thanks.
That's not a deal... However this...
Buyer: How much for bob.com?
Seller: I'd want 50k
Buyer: Ok we'd like to purchase for that amount
Seller: Agreed, how do you want to pay?
That's a deal... He's agreed to the sale.
But yeah, when you're so far into the transaction that you've agreed and it's all in motion it's unethical and probably legal grounds to be deemed a contract.
That's just my view of it but I'm not a legal expert. Would be happy for someone to pick it apart