If what you offer can be "apified", it may be a good idea to publish your API on RapidAPI. They raised 25M in June 2019. So I believe it can become an interesting marketplace for saas / api / app developers.
They take 20%. You can make your pricing plans as you wish.
What do you think? I'm looking for other markeplaces too (AWS, GCP, Pipedrive, Salesforce... etc).
If you have any positive experience selling your software on a marketplace, I would love to hear from you :)!