Recently I have been working on a class project. I have built a Supply chain Dapp, that was based on truffle framework and ganache as a local blockchain. I have some issues regarding the concepts of private Ethreum blockchain.
My question is, is it possible to build a real-world private Ethereum blockchain for a specific organization without any transaction fees and what other costs should I be aware of? And the second question is do I need to deploy my Dapp on Rinkeby? It's just that I read somewhere that you should deploy your dapp to testnets like Rinkeby to demonstrate that it functions well in a setting more like to the Ethereum mainnet. Since I just used ganache for the dapp, I wanted to be certain
I found some answers online but they were not satisfactory, it would be greatly appreciated and helpful if you could provide me with some directions on the subject, as I am relatively new to this. Thank you.