Smartphone apps that pay you for watching advertisements

Got a smartphone? Download AppTrailers and AppJoy+ for residual income while you're at the PC.

They pay you a little bit for watching advertisement videos and trying apps, and let you cash out for Amazon gift cards.

Other apps have other models, such as CheckPoints having you scan UPC codes on specific products in stores in return for points, saving up for gift cards. This will help you save a few dollars on whatever purchases you make. Plenty of steam keys available.

While at my PC, I would look at my phone screen randomly. If I saw that it wasn't playing an advertisement, I just needed to tap a button to load a new video. Doesn't pay much per view, but pennies add up. I managed to save around 40 USD over three months, which I applied to the purchase of some RAM and a video card cooling system.

It is important not to compare this with job income. This is passive income, comparable to having a fansite with an advertisement banner linked to Google AdWords.

Anyone else tried this with these or similar methods?