Nice choice!! Bloodreds are one of my fav corn morphs, and pied-sideds are very cool looking

Corn snakes generally have a life span of 20-30 years, depending on the individual. An average would be around 20, but they can live for longer, so no, if he's only 6 he's not "fragile" at all haha Just in his prime actually!!

As for the price, it's up to you. I'd say if you like him you should go for it. Corns aren't really what I would consider to be a display snake, but they definitely are more active than ball pythons and you probably will see him more often. Most of them have very nice temperaments and mine are always very curious when I'm around their enclosures.