What app can I trim/cut/split whatever you call it my videos in? I dont have any money to buy an app like iMovie

The default video on iPad has a simple trim function. Take the video, go in to the camera roll and open the video. At the top of the screen there is a bar with the video frames. There are sliders at each end, which allow you to select a section of the video. You can then trim the video by pressing the yellow 'trim' button (which gives you the option to overwrite the original or save a new version).