edd1, I am just posting for a few minutes between meetings, but I wanted to jump in with a short answer at least, in addtion to Dr_X's suggestions.
Essentially, when you are advertising a low profit item and you find that your preferred keywords are too pricy - the best strategy is to explore other keyword options, probably using very specific and targeted 2-word or 3-word keywords, rather than very general one-word keywords. (i.e. instead of keywords like 'software', use keywords that are very specific to what you have to offer, like 'widget grading software'.)
Then, be sure your ads are optimized too. That is to say, make sure the ads are about exactly the same thing as the keywords, and that they are well written and informative.
You might want to take a look at these links for more ideas:
How do I optimize my ads?
Lots more info on Minimum Bids:
Hope that helps.