Cheap amazon grinder disc's

I've been on a search for good grinder disc's for a few months now I have been using Lenox MetalMax Cut-Off Wheel those are nice because you don't have to change them until they are dull and they don't shrink but they don't cut very fast and they throw bigger chunks of metal than a standard cutoff wheel so I found These on Amazon and they are cheaper than buying individual disc's at TSC or lowes its about $1.60 in savings per disc and I have been through probably 25 and not a single one has blown up on me plus they come in a really nice thick plastic screw top container that I plan on using for bolts/small parts