Well, there are many different choices for advertising and many of them depend on exactly what you are selling. What type of services do you offer?
Social media, expecially Twitter has done very well for me, so you can try marketing/promoting on the big social media sites.
Also, depending on what services you are wanting to sell, you can find relevant forum sites if there are any, and advertise on them.
As an example, if you were selling SEO services then you would want to advertise where there are better chances of people on that forum that might be interested in those service, like right here on Webmaster Sun.
A lot depends on what you are trying to sell. Just find relevant websites/forums/blogs that will have people that might be interested in what you are selling.