Average Salary: $52,000
Expected Lifetime Earnings: $2,170,896
Lighting designers are often paid by the project, so salaries can vary greatly, but the median is around $52,000 (source). Unless you're a top lighting designer in Hollywood, though, that variance is probably going to be mostly on the lower end of the spectrum. This can be a tough business, and just because you're working today doesn't mean you'll have a job tomorrow.
The way in which you're paid can also vary quite a bit. Depending on the contract, you might get paid hourly or you might make a flat rate for the whole project. If you're designing for a theatrical production, your take might simply be a percentage of the profits.
But no matter what, there's some consolation in knowing you'll definitely make more than the lowly technicians working beneath you. As long as you can yell at someone on set to go get you coffee, you're doing alright.