If you are looking for a way to outsource your advertising and marketing then you should Rooket
It allows you to set your own monthly budget without being locked into a fixed budget or signing a contract. And it operates on a month-to-month basis. It mainly focus on Pay Per Click engines so your site grows according to your budget.
There are lots of free and low-cost ways to promote your site, but most of them involve a lot of work on your part. For me Google AdWords has been the most cost-effective way to launch a new site. It allows you to set your advertising budget and the traffic that you get is first-rate.