There is a website that sells the bands for $35 per side but they are on back order.
https://globaldirectparts.com/oem-lg-watch-sport-w280a-strap/
I found a guy on ebay that sells refurbished ones that he makes with a 3d printer for $70 for both sides shipped.
https://www.ebay.com/itm/LG-Watch-Sports-W280-W281-Band-International-Edition-Band-Gray-color/264520352158?_trkparms=aid%3D111001%26algo%3DREC.SEED%26ao%3D1%26asc%3D20160908105057%26meid%3Da702152ae78749bab702807e6e993c7a%26pid%3D100675%26rk%3D2%26rkt%3D15%26sd%3D274113154120%26itm%3D264520352158%26pmt%3D0%26noa%3D1%26pg%3D2380057&_trksid=p2380057.c100675.m4236&_trkparms=pageci%3A23865cdb-1634-11ea-9552-74dbd180cc50%7Cparentrq%3Ace7dbeff16e0aaa3318ceff1ffe3a948%7Ciid%3A1
Then I found another guy that sells replacement bands on ebay without the antennas, so you have to remove the antennas from your origianl band and slide them into the replacement for $21 for both sides shipped.
https://www.ebay.com/itm/Lg-sport-watch-w280a-Custom-band-Only-for-broken-band-replacement/274113154120?_trkparms=aid%3D111001%26algo%3DREC.SEED%26ao%3D1%26asc%3D20160908105057%26meid%3Da702152ae78749bab702807e6e993c7a%26pid%3D100675%26rk%3D1%26rkt%3D15%26sd%3D274113154120%26itm%3D274113154120%26pmt%3D0%26noa%3D1%26pg%3D2380057&_trksid=p2380057.c100675.m4236&_trkparms=pageci%3A23865cdb-1634-11ea-9552-74dbd180cc50%7Cparentrq%3Ace7dbeff16e0aaa3318ceff1ffe3a948%7Ciid%3A1