What you can do with no account at all
You can turn your web app into a signed Android app and share it directly — as an APK download or via GitHub Releases — with no store account. Users install it by sideloading. This is exactly how beta testing and direct distribution work, and it's fully legitimate.
What each store actually requires
The cheapest legitimate path
Build your signed app first and test it for free. Distribute via GitHub Releases or the free Linux stores while you grow. When you're ready for Google Play, the one-time 25$ fee is the only unavoidable cost. Avoid any service that offers to "publish under their account" — it violates store policies and risks takedowns.
How SaaSToStore fits
SaaSToStore gives you a free signed build with no account and no card, so you can test and distribute right away. When you're ready, you connect your own store accounts and publish under your name — never ours.