Custom Made (plastic/metal) tokens

Check the Web Resources page for a bunch of reference to game parts suppliers.

Many of the parts suppliers can do a variety of custom bits and pieces for you. The cheapest would be the tokens that are just generic shapes into which your or the purchaser would apply stickers. From there the next cheapest would be a 2d outline on a base. Then full 3d plastic or metal sculpting would be the most expensive.

Be prepared to pay some heavy die costs for custom pieces. The cost will average out in the long haul, but will be very expensive for really short runs. The first item I mentioned (the tokens with sticker) are available with no die costs whatsoever. You can include a full color sheet of stickers that will make them look nice for very little investment.