Soundful is inexpensive and you get what you pay for.

I played around with the Free version. The higher tiers may have more options but it seems like the functionality is the same. Essentially you pick a genre/mood/style and then select a template within those ranges. You are then given a number of generated songs to listen to. You pick one you like and use that as your foundation. All you can change is BPM, base notes and major/minor keys. You can’t select different instruments or a song length so the customization is rather limited. The quality of the songs are good and the audio is clear. You have to pay $9.99 or more per month to download stems if you want to customize the sound. Soundful is easy to use and may be useful depending on your need but it is not a versatile song creator.