I bought a huge bulk supply of the stuff they use for drying flowers - which is basically the same stuff they put in those little silica gels pacs in shoe boxes. That, and some activated charcoal from the pet store.
I take a pair of heavy tights; put a golf ball size amount of activated charcoal in the toe; knoto it; fill it from there about 6 inches with the silica crystals; knot again. These go in the skates, and I replace them every couple of months. It works great, and it's cheap - way cheaper than the commercial ones, as I get about 10 pair out of a $17 jug of silica crystals. You do have to be careful not to breathe the stuff in ... and I swing them around a bit outside to get rid of any loose dust before they are used. It works great. Plus, they don't smell due to the charcoal!
Best part is that when the inevitable "I've dropped my phone/MP3 in a puddle" happens, I've got something in house that works way better than the traditional rice in a bow method
Also a chamois in the skate bag to thoroughly dry the soles, etc. Keeps the moisture down all-around. Better than a towel, as chamois are super absorbent.