Fresh ham is essentially a pork leg that's been minimally processed. It's like buying a fresh chicken or a piece of beef, where the meat is sold in its natural state. Fresh ham is often more expensive than cured ham, but it's also more versatile in terms of cooking methods.
On the other hand, cured ham has been treated with salts and preservatives to extend its shelf life. It's like the difference between a fresh apple and a dried apple - both have their own unique characteristics. Cured ham is often sweeter and has a more intense flavor than fresh ham.