Having cleaned myself out for a locker slot, been having the same problem. Mainly because the flame keeps going onto Slime Pit...
Agree about prep costs going down - especially the double-edged ones. I mean, an altar prep is a whopping 50 gold PLUS the disadvantages that come with it. Think I'm OK with locker items staying the same but the prep costs as they stand can make it pretty rough to earn things back given we've now actually got something to spend the money on.