The person you turned it down to may be one of the 581,000 search results for "loan modification calculator", including possibly theloanmodificationcompany.org or loanmodificationcalculator.info coming in at number 11.
In other words, there are 581,000 various types of loan modification calculator sites out there right now.
Now, a year later, you are looking to sell to the "end user"????
Your end user is someone who already has a site and gave up on you.
Therefore, YOU should be the end user and create your own site and try to garner that traffic away from everyone else. The time, effort, money spent on trying to sell this would pay for a site and start earning possibly something.
Honestly, a year later and you are still asking, what should I do with it?