Deltaprintr sells 9 carriage wheels with bearings for $20: http://deltaprintr.com/shop/hardware/carriage-wheel/ Graber sells them for $7.45 each, which works out to $67 for a set of 9: http://3d.grabercars.com/?product=dual-623-v-roller You will also need the usual M3 bolts, washers and nuts: - 3 M3x25 bolts for the axles. - 3 M3 washers as spacers. - 3 M3 nyloc nuts to hold the wheels on. - 1 M3x35 bolt for pretensioning. - 1 M3 nyloc nut for pretensioning. - 3 M3x25 bolts to attach the rest of the carriage.