I wouldnt recommend buying visitors from a site or dont trust too much in such providers. They most of time use bots, softwares or put your link in rotation surf sites which can give you damage if you have adsense or such ads on your site.

Getting a lot of visitors instantly (Unless you have rich contents ythat are very catchy for visitors and attract them), it is suspicious to advertisers and searchengines and they may charge you as inflating traffics.