For low traffic site is very difficult for a webmaster to earn. But there is some way that they can earn the use of CPV and CPI ad networks is the best option for the low traffic sites. This two ads type has differant ways of earning criteria. The CPV ad network will help the webmaster to earn income from every view that recieves to an ad. Most of the CPV ad network offers a pay rate of 0.0005$ to 0.001$. If a site has a low traffic only 50 visitors daily then the CPV ad network pay rates only go with a rate of 0.05$ a day. This amount is not a big but as the potential ability of the site this amount is good. Some of the best CPV ad networks are directcpv, clicksor, edomz etc. Most of the CPV ad networks use pop under for advertisements. But in the case of CPI the rates are far better but there is disadvantages also. Most of the CPI ad networks provide a pay rates of 0.04$ to 0.08$ per install or download. That means as earlier I mentioned if a site has 50 visitors daily from them 5 of them download or installed a software with your affiliating id or banner then the amount will be calculated is 0.06$( as CPI rate)* 5= 0.30$. As comparing with CPV ad network this rates are far better but the disadvantage is if the site not able to find a downloader a day then no earning will comes on that day.
For earning with CPI ad network the webmaster need to get 2 to 6 downloads a day. The best example for CPI ad network is the UC union which offer a rate of 0.04$ for every UC browser download comes from the referral id. Both the ad networks has its own advantages and disadvantages but the downloads or views are developed according to the skill of the webmaster. All the best.