Any ideas on what this website with 50,000 email addresses would be worth?

Hi,
I have a website www.cruisediscountgenie.com that I had built for me back in 2010. My designer used Joomla to build the website. The idea was that a person could enter their email, select a cruise they were interested in or had already booked and the website would then check the price daily. If the price dropped the person would get an email notifiying them of the drop and they could book the cruise or request an onboard credit. I monetized it a little back when I had it built and made moderate ($1000 or so from display ads etc) money but then forgot about the site and worked on other projects.


I came back to the site last month and found that it now has over 55,000 email addresses in the database. Looking at them (I didn't go through all of them) I would estimate 10-20 thousand of the email addresses are good addresses from people that signed up to use the genie. It could be higher but I am not sure. In total there are 55,996 email addresses in the database and it grows each day.


With a database of emails that size what would the website and list be worth? I have not tried to monetize the list and those that are on the list will most likely be interested in travel, travel clothing, etc.
If sold the new owner would have to transfer the emails over to their provider as the email program built into the site is at its max capacity.
Any ideas would be helpful as I am looking to sell the site as im working on other projects.


Thanks Everyone
Scott