you can get bands for under $8 on ebay etc, or even local shops and markets. theres millions available, it just a standard 22mm band, nothing that special about it
its hard to find specific S20 bands, but one that fits any of these are the same band; Garmin Forerunner 620/630/735XT/220/230/235
i bought a silicon one, and i reckon its heaps better than the original.
