You don't really need distilled water. If you were going pour it on beads or a foam device you would, but you can set a glass of regular water in your humi without any problems.
When you do get beads just bring a pan of water to a good boil for a few minutes and put the beads in a colander and hold them over it, the steam will recharge the beads. You might want to try that selling iceberg water thing a shot. You'll probably get rich.
Bottled spring water??? Contaminated by the pollution in the ground! But from the great north pure iceberg water. Natures best. :tu