Photoshop does the job in one step rather than two, but as you points
out it is expensive. I have also tried separating images with Photoshop
Elements, a cheaper stripped-down version of Photoshop, but was not
satisfied with the results.

Bill

If your scanner does not inclue an automatic recognition of various
items placed on the bed, then using the FREE Irfanview, could be a
better solution.

However - with both programs mentioned, making a 'second step'
involves loss of information unless an intermediate -=lossless=- file
format is chosen.

Irfanview does allow you to select a TWAIN source [scanner] and thus
bring in the multiple stamps, separate and save. It's not as elegant
as PS [rotation is much harder than using PS's ruler], but it is FREE!

http://www.irfanview.net/