Ponzi has 100$ and up.
I just want create btc web wallet where users can deposit some funds if they want(10% month, thats just number)
thats is like bank, where you open you bank account and if you want you can deposit your free funds to saving account.
I think you're confused on how it works.
Wallet is not equivalent of bank. It's just a piece of software, it won't generate you any income.
If you want to earn % on your bitcoins, you'd need to invest them somehow. Note that any entity that guarantee you x% income on your bitcoin holding is most likely a scam.