Mash-tun, aluminum boil kettle (looks about 8-10 gallons but I'd ask), and CO2 regulator with Sanke keg connection. The Sanke connection is nice for commercial beers, but few home brewers futz with commercial beer kegs, preferring Cornelius/Firestone type soda kegs, of which most use ball lock connectors. That's an easy and cheap conversion (I have done it during parties), the important thing is the regulator. You'll also need a CO2 tank which you can pick up for a hundred bucks or so from any welding shop who will also refill it for you when empty. I've found 10 pound tanks are the best compromise between weight and capacity.
Despite suggestions, there is no carboy in the picture, unless I'm blind. You still need a primary fermenter (secondary is optional) ($30), racking cane ($12), some empty Corny kegs ($30/each), a hydrometer ($7) and thermometer ($10) at a minimum, but this will get you up and running.
He likely did batch sparges as I see no other coolers, which is fine and what most people here seem to prefer from a time and efficiency standpoint.
Any of the three items shown is worth more than the $25 asking price, so go nuts.
