The currency of The Grand Canyon area is called chips, these actually being poker chips from casinos brought in by the last survivors who arrived from Las Vegas to seek refuge at the Hoover Dam Garrison - just before it became entirely closed off from the rest of the world, at around 2058.  Currency has no weight.
1 Blue Chip = 100 White Chips
1 Red Chip = 100 Blue Chips = 10,000 White Chips
1 Yellow Chip = 100 Red Chips = 1,000,000 White Chips