If you're charging true customer rates something like......
$1.65 for vans.
$1.95 for loads requiring Sprinters.
$2.25 for smalls.
$2.75 for larges.
$3.00 for small semis.
$3.50 for full semis.
NOW, you will have to adjust ALL of these based on what they will actually PAY for.
But start...