Creating a list of websites, delete duplicates

Hi, I'm creating a list of websites on a certain topic (which one, not important), for my own use. I'll not publish it anywhere. I list only domain names (homepage of websites). Something like : [login to view URL] [login to view URL] [login to view URL] etc. Until now, I used a text file and entered each website address by hand, but it's a tedious task, because for each address I need to check if I already entered it or not. I need a very simple tool to delete duplicates, that I'll install online. With or without a database, it's up to you. At the end, I'll have probably about 3,000 references. My hosting has PHP installed. Very basic interface : a box to enter websites address and a submit button. I should be able to enter several addresses at the same time. Because I get addresses from Google searches, online directories or other sources, sometimes the address has http and sometimes https, and has www. or not. So you need to take this into account. All these 4 possibilities exist : [login to view URL], [login to view URL], [login to view URL], [login to view URL] Take also care of the domain extension : "[login to view URL]" is not the same as "[login to view URL]". I need something very simple, so cheap, because the work is easy and I guess quick to do. Thank you.