Dan,
Don't be ashamed.  I have grown tired of the slow payers, no payers and the ones who constantly ask or tell you to lower fees. 
Now, when contacted by a new client I just ask them - "How much do I need to pay you to let me do your searches?" 
This usually stammers them for a few seconds, then the ask for a fee sheet again.  I say "we don't charge for searches anymore, in fact we are willing to pay you.". 
After stunned silence, I usually get a quiet laugh and then, no really, what are your fees? 
I ask them if they pay within 30-40 days, (they always say yes), then I say great, I have an application and a form for you to sign that includes a personal guarantee from one of the owners.  Once I receive that back, I would be happy to give you prices.    ... click...
Hello,  Hello, Hello
Problem solved.