They have a lot of Thai songs (a super thick book) although the newest songs are about 5 years old. You can call in advance to make a reservation. $1 before 2pm per hour per person. We went during their prime time and it was $7.25 per hour per person. We got 3 microphones for 3 ppl and it was awesome! You can bring your own food!
Review Source:Definitely the most affordable karaoke I've tried in the Bay area. For what you pay, it's a fantastic deal. The song selection is off the charts, room availability is rarely an issue, and the front desk man is very nice.
Note that it is really cheap though... that means a small room with less than ideal sound equipment.
All in all, Gamba is a great place to get your karaoke fix without forking over an arm and a leg.