[Alavinus]

If you are not driving the omniwheels and want some cheap alternatives here they are:

You could always order some Delrin or Teflon and make skis to support the robot

If you just need a low friction wheel take a sheet of plywood or normal wood and cut a twelve inch circle with a jigsaw. Then take some slick material (thin teflon works nice) and then use wood screws and sink the heads below the surface (no metal cleats) This gives you a nice big wheel with very little weight and friction.