Often the data is public and free. But it's your job to drive down to the county clerk's office, make a photocopy, bring it home, scan it in, and use OCR or something to convert it to a format that can go into a database and be searchable on your web site.
That's the value added by lots of these web sites that publish free public data. They've done all the leg work.
If the city is going to publish the data in electronic form and pay for the bandwidth for people to obtain it from them, then there has to be some benefit to the city. If there isn't, then you have to drive down to town hall and photocopy it like everyone else.
Your best bet is to pick what kind of information you want to obtain, and then call your town hall and ask them if they have an electronic feed where you can transfer that data from them. You might find that you need to write a scraper to, umm, borrow the data from your town hall's web site.
