What is the easiest way to buy ETH?

Could you kindly elaborate on the simplest approach to purchasing ETH? I'm quite new to the world of cryptocurrency and am seeking a straightforward method to acquire Ethereum. Would it be through a centralized exchange, a decentralized platform, or perhaps another avenue? Additionally, could you provide insights on the associated costs and any potential risks involved? I'm eager to understand the entire process and make a secure and convenient purchase. Thank you for your assistance in navigating this new territory.