Depending on the amount of traffic the business listing sites receive they would usually try to monetize their website with online business listings, adsense, featured ads, add banners etc. Like Dave said you could list your business on all of them only by doing a few a day. It really doesn't take that long to do and who knows maybe someone clicks on your listing and makes use of your services.

Free business listing > client > Rxx,xxxx for a few minutes of effort? Besides that if they allow you to add your website address you could increase your google rankings a bit as well.

If you really don't want to do it I'm sure you could find someone on Fiverr to do it for you for a few bucks.

Good luck.