Am throwing together a pretty simple quoting system for work to take some details for a product and based on material cost and a table of fabrication costs spits back an estimate for the product.

At the moment before it is made pretty and nice, its just using a htaccess with a few usernames in it to keep it out of the public eye (its for retailers not end users)

But going ahead it will need possibly 100's of users in it, and there has already been enough problems with forgetting passwords etc, so I need something that will allow for users to change them, check they are not stupid passwords, log all the logins etc, allow for password resets and not really much else. So a whole CMS is total overkill for it.

Is there anything else free, in PHP that I can use to look after doing these?