I changed the padding on my helmet. One can purchase replacement helmet padding from about 15 USD from aliexpress I think but I never seem to take it off an wash it (I find it disintegrates) so, rather than velcro helmet padding, some simple self adhesive padding would be fine. I found some shoe heel pads at 20c a pad and three seem to do the trick for 60 cents (or about 60 yen).
Shoe Heel Pads as Helmet Padding by
Timothy Takemoto, on Flickr
I also have bought some dérailleur jog/pulley wheels, and a rear light and some elastic shoelaces from China. They all arrived at the same time on Christmas day.
Bike Bits from China by
Timothy Takemoto, on Flickr
While not strictly a bicycle related item, the elastic shoelaces would work even on non-competition cycling shoes since they are quite tight.
Elastic Band Laces by
Timothy Takemoto, on Flickr