That is my hunch too. You might break even, but barely, and it'll take selling everything. For rough estimates: $25-30 / carboy (total $180), $40/keg (total $120) that you want to sell. Not really sure what the co2 tank would sell for, and the regulator maybe $35. Maybe $20-30 for the mill and $20 for the capper too. The rest of the stuff will sell for a couple bucks here and there. That brings your total to ~$400 plus whatever you can get for the little pieces.
I have done a couple giant buy's from craigslist and each time got a LOT more stuff than that guy is selling for less money. Granted they were absolute steals and I was lucky, but IMO too much effort and money up front if all you want is a keg and a carboy.
Just my 2 cents.