DH and I came back on Wednesday with cases that weighed exactly 50lbs, I frankly can't imagine taking anymore back they were so heavy. 100lbs is quite a lot and I'd suggest getting a duffle bag (a simple one from REI that weighs mere ounces) and a really lightweight case. We invested in a pair of light weight, hard sided Samsonite cases that I found on sale for $70 each online. Another thing to consider would be using a sturdy cardboard box, or even a plastic one that you can tape up.