If you know anything about Photoshop, there's a free equivalent that you can download called GIMP (odd name, I know). If nothing else, you can go to cooltext.com, create and download some fonts for your videos, then go into GIMP and paste the downloaded text onto a screenshot or something. It makes it look a lot like the stuff from bigger channels.
Actually, GIMP has a feature called the fuzzy select tool. By adjusting the Threshold level, I think you should be able to take a picture of yourself and then click on and delete the background, so you could put a picture of yourself over something.