I have not done it but I think its kind of a waste, there isnt much long term benefit. Better to invest that money in some quality articles and guest post somewhere
I've tried a few 'paid to click (PTC)' sites to get traffic to my site. It was extremely useless, about only 0.1% of the users who clicked the ad made it after my site's front page Waste of money if you ask me
buying traffic i think not a good idea, there are some ways that we can get traffic without paying, I think most of paid traffic are fake )) some people get huge traffic from facebook pages..