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.
Not sure what you're asking for or if you don't understand Bitcoin. You can show off your public key to the world and anybody can deposit funds to it (you don't need a web wallet).
It sounds like you want a banking account and a savings account. Why not just have 2 different addresses? Or a key pair for each transaction...