Yes, I have used several of them. You can forget all of these type offers: "Buy this and you get tons of traffic onto your site"!
These may bring you some numbers when you look traffic reports, but these numbers don't represent any quality traffic. These visitors are absolutely no good for anything. Traffic exchanges aren't very useful either.
I have had some minor success with free automatic traffic builders based on article submitting, but it was a while ago. And the results didn't match with efforts, so I wouldn't success these either.
But there is some software what helps you to build traffic. You have to do many things to yourself though. For example: On-page SEO. You have to make the desired changes by yourself but you can know what to change with help of some software.
Also out there are many different types of blueprints, courses and other types of learning software what teaches you to make effective efforts to yourself. You can build traffic quite well by yourself if you know what you are doing.
I know a webpage- http://GetTraffic.Freeiz.Com
It's not big nor beauty, but there's some useful information you might to look at. Different aspects of traffic building are explained and as I see, new articles are added often so I think that this may be becoming a good source of information to anyone with traffic problems.
Cheers and keep up good work!
Sincerely
Max Magay