wheels 2 $4.99 $9.98 n/a Home Depot http://lawn-and-garden.hardwarestore.com/78-496-lawn-mower-wheels/plastic-wheel-206938.aspx Caster 1 $4.00 $4.00 n/a local Harbor Freight Motors 2 $16.95 $33.90 $7.00 online http://www.allelectronics.com/ plastic platforms 3 $10.00 $30.00 n/a local 3' threaded rod 3 $0.50 $1.50 n/a Home Depot "1/2"" collars" 2 $0.25 $0.50 n/a local Motion ind. "1' 1/2"" shaft" 1 $1.00 $1.00 n/a local 48 tooth #25 sprocket 2 $5.76 $11.52 online Robotobjects.com 12 tooth #25 sprocket 2 $4.80 $9.60 online Robotobjects.com 1' #25 chain 2 $3.50 $7.00 local Motion ind. #25 chain clasp 2 $1.26 $2.52 local Motion ind. "3""x4"" plastic wheel mount" 2 $1.00 $2.00 n/a home made "2"" U pipe clamp" 4 $1.00 $4.00 n/a Home Depot Misc hardware 1 $3.00 $3.00 n/a local Nut and Bolt Supply $120.52