So if you are using a webcam to record while recording a game you can use OBS to do so and you can move the your webcam preview to anywhere on the screen over your gameplay preview. At that point you can record both at the same time and you will have one video file to use in your editing software.
If you are using a camcorder as a facecam they you are going to have 2 video files to deal with in the editing software and you will have to do some syncing manually. Also if you are going to use this route I recommend that both of the video files are the same type (MP4).
I know in Adobe Premiere Pro you can put a video on top of another video and you can the resize and move around the video on top to anywhere.
If you are a student you can get the whole Adobe suite for $20 a month.
My advice for now, is use the webcam instead of the camcorder in OBS because that is a lot easier to do than have to deal with multiple video files and manual syncing, and save up until you can afford a good webcam.
Another tip to make your cheap webcam look good, is good lighting. The more lighting you have the better quality of the camera.
Good Luck!