I'm the same way with the Sharp EL5100. Had my first one when they were new, lost track of it, bought another and lst it in a house fire, bought another and lost it when I went into the hospital. I've probably spent 500 dollars on EL5100s and I still don't have one. Cool older calculators are worth a lot of money, an EL5100 now in good shape will set you back almost 200 bucks and they cost like 60 new.
Ebay has your Casio. There's one on there now for 100 bucks.