So im making a buying/selling website, where people can search through my catalog. and i have no idea how i would go about that. basicly i would have a database with all of my producs in it, and then people would type in a key word and a page would come up with the appropriate results.

Thanks in advance!

P.S. even if you don't know how to do this, if you could just point me in the right direction id apreciate it!

You can simply do this with php, and include some ajax to make everything easier for the user, I don't know anything about ajax :p
with php you will have to make a html form like this:

<form action='example.php' method='post'>//or an other page or get
<input type='text' name='txt'></form>

Here you will need to do some queries to get a product from the database and show it to the user.