How can I include commas in Prism's axis numbering (i.e. "100,000")?

Prism (up to 4.01 and 4.0b)  never includes commas in axis labels, so graphs "100000" not "100,000". There are two ways to work around this limitation:

1. Change you units so the label is "100" and the title is "Thousands of cpm" or whatever.
2. Use custom ticks. From the Format Axis dialog, choose Custom Ticks. From there you can plot any text you want (text or numbers, or numbers with commas) at any coordinate you want. Create one custom tick for each number on the graph. For example at Y=100000, plot the label "100,000".

Prism 4.01 and 4.0b and later let you choose whether you wish to include commas (a choice on the Format Axes dialog).