I bought IndieHackers.com for $2000.
I sent an email to the owner, who was a tough negotiator and refused to budge on the price. But honestly, I just feel lucky that he wasn't using the domain and was willing to sell it!
Things got wrapped up pretty quickly. We agreed to terms in less than a day, signed up for Escrow.com the next day to handle the transfer and the payment, and the day after that it was done.