Are you talking about the plastic piece that snaps into the arm that comes out from the handle? I think that's a commodity item you might be able to get at an outdoor supplier that sells parts to fix backpacks or a luggage repair place could maybe even do the repair for you. The trick to replacing it will likely be ripping out the stitching holding it in place and then sewing it back. With cost, keep in mind that a replacement bag can be had on eBay for around $40, give or take.