I would like to search through five years of tabloid newspapers for certain keywords. The papers I want to use are not available online or on LexisNexis. There are media intelligence companies which scan in newspaper articles and then (for a fee) perform a keyword search. I don't have the money for the fee.

However, one company offers a free trial. I would probably get enough information from this free trial for my purposes.

Do you think this would be okay? How would I handle the acknowledgements or the references?