Hi! I am a soundtrack composer & designer, I work with FMOD as well if you need it. The amout I´d charge you depends on the length and complexity of the tracks, but it could go around 200-400. But we can talk about it if you want, here´s my portfolio and web:
https://on.soundcloud.com/fnVA1bk6h8oz2pHh73
https://sites.google.com/view/davidarrublacomposer/portfolio-services