You may decide to create free videos as extra content for your blog, and not sell them at all. If this is the case then you can still make money from these videos by selling advertising space on them (in the same way as discussed for monetizing podcasts). Once you have high volumes of traffic visiting your blog, and watching your videos, you can charge businesses to advertise at the beginning of your videos. Use website’s like Izea to help you connect with companies willing to pay to advertise on your blog.
If you have a good idea for an app, and the skills to create it, then producing your own premium app can be profitable. However, with so many free apps available, it may be hard to convince people to pay. If you want to go down the premium app route, consider having a basic free version to encourage people to download the app in the first place. You can then provide the option of upgrading to a premium plan once users realize how useful the app is.