There is a small bug in Snow Leopard's Preview application that has to do with the search features of the program when finding text in PDF documents. When you look for a specific dollar amount in the PDF document, it will not only locate the search query but will also find irrelevant search results.
This bug was brought to my attention by CNET Forums poster "scotty321--2008", who outlined steps to reproduce it:
Generate a PDF document with dollar amounts in it (use any text editor and use the Print as PDF feature).
Open the PDF in preview.
Do a search for a dollar amount where the number either before or after the period exists in the document.
Here are some search results for a PDF I generated, which demonstrate this bug:
This behavior seems to be from the program treating periods as separators for search queries, instead of using them in the search results. As such, in the PDF shown if you search for "50.00", Preview will display any instance of "50" and "00".
A fix for this bug will require Apple to address it in an update, but you can help them be aware of it by submitting a bug report here (requires an ADC membership, which is free): https://bugreport.apple.com/
Alternatively, you can submit feedback at Apple's OS X feedback page (Select "Applications/Utilities" as the feedback area): http://www.apple.com/feedback/macosx.html