How to buy extra baggage cheaply?

Hey there, I'm wondering if you could offer some tips on how to purchase extra baggage on a flight without breaking the bank. I've heard that airlines can charge quite a bit for extra luggage, so I'm looking for some clever ways to save some cash. Any advice on how to find the best deals or negotiate with the airline? Also, do you know if there are any credit cards or loyalty programs that offer discounts on extra baggage fees? I'd love to hear your thoughts!