If you do not have any limits, the ad will be shown and clicked as many times as your Traffic Source allows.
RedTrack provides you with an option to change the ad display frequency for each unique user
(it can be done from the Offers tab upon submitting a new Offer):
The cap may be set to any number of visits per day/week/month you choose.
And for each new UA or IP:
Keep in mind that all visits outside of your set limit will not be accounted towards the events included in your RedTrack plan.