Atlantic City did (or still does?) have color standards for each denomination:
$1-white; $2.50-pink; $5-red; $10-blue; $20-yellow; $25-green; $100-black, etc.
See the Borgata line up here:
http://chipguide.themogh.org/cg_chip2.php?id=NJACBA&v=4293188234

Other jurisdictions didn't have firm standards, though common colors are $1-white or blue; $5-red; $25-green; $100-black, and others for the big chips. There are many exceptions though. For example, California often used $5-yellow.

Fractional colors varied over the years, but 25c was sometimes orange or brown; 50c sometimes purple.

Lower denominations, especially fractionals, were hot-stamped for cost savings. Also $1 hot stamps sometimes. The inlays often started with $5's and up, though many exceptions there too. Same theory for the inserts. Often, no inserts for fractionals thru $1 (or $5); start inserts with $5 or $25 and above.