cool - how do you get those mealies so cheap? 
also, the ones that are left out - you should gutload them to give them nutritional value to your leo. i assume that the substrate that the mealies were placed in are saw dust. it's something the mealies can't really eat and should be trasferred to substrate that they can eat
right now, i just got done transferring 100 mealies from the sawdust to the gutload. i used to feed my leo those mealies straight from the sawdust, but everyone in this forum told me to gutload
and from all their input, i made a blend of different foods to create my little gutload 
my gutload includes: fish flakes, oatmeal oats, wheat bran, powdered non-fat milk, t-rex sandfire cricket gutload formula, and this other feeder gutload formula. also, i put a thin peice of paper towel and placed an apple slice on top for their water needs.
of course, you dont have to use everything i just used...lol
i just kinda took in a mix of what people were telling me they used. also, i hear if u use a carrot as the mealies' water source, it tends to mold slower than apples, so you don't have to change it as often as me....
anyway, i hope this helps!
aimee
-----
1.0 Albino Leopard Gecko (Melvin)
1.0 Black Lab / Pitbull mix (Mikey)
1.0 Blue Fighting Fish (Blue Balls)