How much Ethereum does $100 dollars buy?

I'm just curious, given the current market conditions, how much Ethereum can I actually purchase with $100 dollars? It seems like the price fluctuates quite often, so I'm wondering if there's a way to calculate it accurately. Or does it depend on the exchange or platform I'm using? Is there a general rule of thumb for converting fiat currency to Ethereum? I'm just starting out in crypto investing and would appreciate any clarity you can provide.