Adding on to @pabloruiz55's answer:
how much ETH should I have in my wallet to create this smart contract?
The transaction fee for deploying a smart contract depends on its content. You could estimate the gas required for contract creation from remix-online solidity compiler.
- Simply paste your code in compiler tab
- Click on
start to compile to compile the code
- If the code is compiled successfully you could check the gas required for deploying your smart contract.
- You could also get estimated gas for all the function of your contract (including transfer)
Ethers required for a transaction (including deploying a contract) is governed by a formula:
transactionCost = gas*gasPrice
You already estimated gas from the remix and you can choose gas price as per your convenience. For reference of safe lowest gas price have a look at eth gas station.
If you supply more gas than required in creating a contract, the excess gas will be refunded. So try sending the gas a bit higher(but not too high) than that estimated by remix.
After creation of my new coin "Ghost", and when someone want to send
10 Ghosts to another one, what about the fees of transaction, will it
be in ETH or Ghost?
The transaction fee will always be in ethers and the transaction fee could be estimated in the similar fashion as for contract.
after I deploy the smart contract on mist what the next ?
After you deploy taken successfully. You could design a UI for users to interact with the coin or try adding your coin on some exchanges or do whatever you designed your coin for.