I frequently receive inquiries on the subject of how much should be charged for a typical karaoke performance. The rate varies greatly from area to area. Your experience, sound system, and song collection also figure into the equation. My advice is to contact several comparable karaoke companies in your area and inquire about their hourly or per show rates. You may need to do this under the pretense of being an establishment owner or booking agent to receive accurate quotes. Some may think this to be a little unethical but I simply consider it business research.
Promoting your karaoke company is basically like promoting any business. Placing an ad in your local phone book yellow pages is always a good idea. You might also place a weekly ad in some local newspapers. The fastest results however, will be acquired through foot work. Make up business cards and fliers and hit the streets visiting every establishment that is known to hire live entertainment. You may want to offer a low, first performance, introductory price to get your foot in the door. I have found that the best time to visit these establishments is in the afternoon. This is when they are normally the least busy and there is a better chance of speaking to the owner or manager.
There is one point that I cannot stress strongly enough. Never perform at lower than the average going rate or undercut the price of another company just to get the job. This practice hurts everyone in the business and will cause you to rapidly lose the respect of competitors. You really don't need this reputation. Earn your position in the business with hard work and professionalism. Being energetic and innovative along with keeping your system and song collection up to date will assure you a place in the market.