If you just want to go to the "kghzi" peninsula with the most popular beaches during the summer, then vans make frequent trips from Yerevan for cheap. Throughout the year you can take the Ijevan/Dilijan/Noyemberyan vans marshutni and hop off at the lake as well, or depending on where you want to go in the region you can take a van directly to Vardenis or Martuni or Kavar. There is a train that can take you to the peninsula, and then continues around the top of the lake over to Shorjha, a beautiful spot. Unfortunately, the train, while cheap, does not earn rave reviews.
