Depending on where you live, a restaurant liquor license can cost $500 or as much as $70,000 (p.s. I wouldn't recommend PA) and the majority of towns and more rural areas have a liquor license quota, so you may not be able to get a new license at all. To top it all off your license needs to be approved by the towns council and that requires a obnoxious "processing fee". However if you buy a bottle of yagermeister for wholesale cost (assume $15) you charge $8 for a mixed drink, how many shots are in a bottle. The roi on one bottle is insane and if you have a whole bar full of these money making machines, your set. The only thing i'd add is an amazing environment that makes your fan base love your business even more to keep 'em coming back!
Best of Luck,