Buying traffic sounds like a bad short term solution for a longer term issue.
While I believe there may be some positive results from getting a bunch of fake traffic to a site, blog, facebook, or twitter campaign, what do you think your client would prefer?
1. Purchased traffic that fakes out Google temporarily, with the possibility of punishment and other repercussions?
2. A legitimate campaign that reaches out to their current customer base, and allows for an organic following of their site, blog, twitter, facebook?
I know as a small business owner, I would realize that the second answer might take a lot longer, but would be superior to number one if the correct strategy is put into place.
As many of the recent SEOmoz blog posts point out, building a friendship and loyalty between a business/site and their customers is absolutely key. It should be approached as a fledgling friendship, and the rewards will be real when one if finally developed.
As far as a specific Facebook "like" campaign goes, start with the basics. Have all of the owners and employees follow the business in question, and "like" and/share all the likeable shares and posts.
Before this happens it would be advisable to have these same people ask them to follow the business as well.
Hope my suggestions help.