The cost will vary depending upon many factors, such as event size and scale. But, if you are trying to figure out the cost of lighting and sound rental equipment for your next event, two aspects can help you determine the amount. Let me give you some ballpark figures.
The quality of the AV equipment you rent is also a factor. You will, of course, pay more for state-of-the-art lighting and sound equipment than outdated equipment. So, ensure that you receive a quote within your budget based on the AV equipment quality, age, & performance standards.