Hot linking (using someone else's bandwidth to host files to send your users) is generally frowned upon, since bandwidth isn't free. I'm not sure aware of any sites that just let you do that for free with audio files (which are typically huge compared to something like images) without using their own dedicated players (i.e. ads). There are ways to use Dropbox and Drive for this, but I think your best bet would be to try to host your game in a place that allows you to also host your assets, like Itch.io.
You can use some other places, like GitHub, but be mindful of the bandwidth limitations. Something like GitHub pages is usually more appropriate for testing or limited releases; you can host apps there but you may outgrow it, especially with audio files being downloaded. Other than that, you may want to look into a CDN. There aren't many that are completely free, but cloudfare has free options.
I would probably suggest hosting on itch.io and offering a downloadable version there as well when it comes to audio.