Udimi is a marketplace to buy and sell internet traffic. Udimi make sure that buyers get 100% legit traffic via Udimi filtering system and by making sure that buyer's and sellers are transacting to a real person as well.
Getting quality traffic from Udimi is not "free". You need to buy them from Udimi legit sellers. I will recommend you give time to read Udimi Help section to know more how the platform works.