Generally speaking, For domestic flights, one bag, up to 50 lbs costs $25. International flights will get you 1 free checked bag. I've thought of this as well.

Generally speaking, For domestic flights, one bag, up to 50 lbs costs $25. International flights will get you 1 free checked bag. I've thought of this as well. It's actually not very practical. Check out UPS shipping fees. Except in very edge cases, they are way more expensive than taking your bag with you.