What is the cheapest way to deposit fiat to crypto?

Hello, I'm curious about the most cost-effective method to deposit traditional currency, also known as fiat, into the world of cryptocurrency. With so many options available, from bank transfers to peer-to-peer exchanges, it can be overwhelming to determine which route offers the lowest fees and best value. Could you please provide an overview of the cheapest and most efficient ways to make this transition from fiat to crypto?