How to make purchasable content in my game?

Good evening,

I'm working on a multiplayer game where every player has a set of different unlockable and purchasable characters. I'm planning to use purchasable in-game money for this so I wanted to ask two questions:

1. What service should I use for this? Does Unity have something implemented already or is it 3rd party system?

2. Do I need to have a database to keep information about all players' accounts, amounts of money and currently unlocked characters?

Thank you very much for the help and sorry if I'm dumb, because I'm really new to the commercial part of development.