itch.io

Music can be rough. If you've got a budget for it, I'd recommend contracting out for your music. You can expect rates anywhere from $10-70/minute  depending on the musician - and some might be willing to do it for free (you'll also potentially get discounts if your music is non-exclusive, meaning they can offer it to other developers/groups) or at discount/special rate if they're credited and/or are offered a revenue stream, such as if you include the game's soundtrack for sale or link directly to their bandcamp/site from the game.

If you just want one or a few throwaway ambient tracks to include in your prototype while you get that sorted and don't have much money to invest in your game for contracted music, feel free to reach out. I can do at least that much for you for free - though they won't be as high quality as you'd get from contracted musicians.

If you don't know anybody in the music sphere, I'd recommend reaching out to Artem Bank or Daniel Swearengin. Both are very friendly and affordable musicians who do good work with a fast turnaround (though I admit it has been a few years since I last spoke with Mr. Bank and I'm not sure how active he is these days) - also they won't rip you off and they play things straight and fair.