Background music for Motiviational Shorts

I have a bunch of motivational shorts for which I need suitable background music (without overriding the speech).

I would like this done in batches of 20 shorts at a time. No video editing is required, you just need to include a suitable background track for it. I would expect 20 video files with generally different background tracks but its ok if certain tracks are re-used if they suit the short etc.

PLease propose a quote for processing 20 shorts at a time. Thanks.