I don't know if it would be wise to just dump things into a text file or not. Yes, it will be simple to search and require less coding on your part. But on the other hand if you store everything in a database you will have many more options for how to manage the data in the future. For example, you would be able to write a form that only displayed items of a certain property. If you have 1000s of items I imagine this would be useful.
Using a plain file will have no affect on which machines can see the data since the database and all of the code the manages the db is server-side. Once you get the server set up, anyone with a web browser should be able to use the interface and view the data.
The big advantage to using a simple file for output is that if you are a novice php coder it will be much simpler. Just check out the entry for fwrite() in the php.net manual:
http://www.php.net/manual/en/function.fwrite.php
That manual, by the way, is just about the only reference you'll need when getting started with php. If you get ambitious, check out the mysql functions as well.
And you can always write the app to store data in a text file for now and then write something to convert the text file into mysql tables when you feel ready to start using a database backend.
Hope this helps!
--Brad