You'll probably be looking more around the 100k mark than the 50k mark because most slimeballs cost around 80r.
Doesnt matter now I sold him what he needed.. There is more to this world then money, there will be plenty of time to think about value with the new shopsystem - for now i say we just have fun!
on SMP1, ill rather deliver them to you.. If i set up the chest others will buy them (Im at your res now with em on SMP8)