Ivan, there is a book called "The Chip Rack" - ninth edition which is a price guide. Prices are only a guideline to go by. Here is what the guide says:

$1.00 Blue - Value Code "D" ($10-$14)
$5.00 Red - Value Code "C" ($5-$9)
$20.00 Lavender - Value Code "F" ($20-$24)
$25.00 Green - Value Code "F"

Hope that helps you a little. This book was published June 2002. These values can change based on supply and demand.