The "simple" method of making your own sound effects. As an addition, you don't "have" to use your own voice. Record sounds around the house and mess with them. Heck, the Nazgul bat creature in the Lord of the Rings is just a donkey neigh slowed down!
Last note: after you've made the sound you want, go to "Render As", and look for the audio option. There you can render it as just an .mp3 file.
Thumbnail: pixabay.com
