Need To Know
There are some concepts you need to know.
The smart contract in Solana we call it
program. The program don't store any data. We store data in the account owned by the program. In Solana, every account has a program as an owner. Only the owner can modify the account's data. Takes the token program as an example. You will create an account belongs to the token program and you will transfer token in the token program. The token account will store your balance back to the account it owned.
You need to pay a rent if you want to keep your account alive. The number depending on how much size you use. Luckily there is a way to get the rent exemption. When your balance in the account bigger than or equals to the number which worth 2 years rent. You can use RPC
getMinimumBalanceForRentExemptionto get the number.