Can you give more info. Where are users from. How unique are users. No bots.
Easyhits4u is most popular manual traffic exchange site. They have over 1m ragistired users and there are no bots. You can check out the site and read reviews about it, there are a lot of positive feedbacks. Earning credits is very much time consuming, therefore they are relatively valuable. Normally, 1 visit costs 1 credit but you may choose where you want visitors from. In that case, credit cost per visit may be increasing depends on the location. I can find out exactly credit cost if you let me know the country you wish visitors from.