Completely possible, if you are comfortable using Craigslist and live in a fairly densely populated area. The cheap way to go is to buy a used chest freezer ~$100, CO2 bottle and regulator ~$100, 2 kegs $30 each, and a temperature controller from Amazon ~$40. You will need some hoses, but you can just use party taps until you want to build the tower.
Sent from my XT1635-02 using Tapatalk