Car key question

Hello!
First off I'll admit I'm a new(er) car noob! My last car was a 87 Buick Park ave that I've had since 97 and treated me very well, but it was time to upgrade.
After some looking around decieded on a 2000 Buick Century custom. Found one about a week ago.. Drove the old one in and the new out in a few short hours.. Through all the paper work I really never thought about extra keys.
Now I finding out this might not be as easy as stopping by the local hardware store. ? Gotten mixed answers from co workers. some swear there coded. Others say its just a slug mounted in plasic to made contact, but for what? IMHO the bell that goes off when keys are in and door is open.
I called the dealer tonight and was told I would have to go to a "Buick" dealer" to get a set made. UH?
Best I can describe the key is that theres a little black square below the key head with little silver contacts on both sides. I pulled the grippy off the head and for sure there is NO microchip in the head.. its just plain to flat to do so. The next thing I was going to do is ohm it out to see, but hesitated sending a few millivots though somthing that MIGHT be coded.. I also imagined the Wifes reactions if my attempt failed and wreck the key. :(
I Just dont want to get ripped off having spare keys made and any info would be great.

You've got pass-key II. The little ship, I believed, is not coded, per se, but it is programmed to work only with your car. They are quite pricy though.

Thanks. Fould a place today that will make them for like $50 each.
Some sorta resistor thing in the plastic.. Not just a slug.

That chip in the key is a resistor and it is safe using a meter to check it. That is one of the checks we do when we suspect a Pass key 2 problem. 50 dollars seems high to me, what is the dealer charging? Also I have fixed many no start problems becuase of aftermarket keys.