Really easy question about a really stupid 'whoops'

[Craptastic!]

Some time ago I lost the keys to my '93 Ford Taurus, however I was in luck..atleast so I thought. My cousin, the previous owner of the vehicle, had spare keys, turns out that he only had two ignition spares and a spare for the trunk. This leaves me with out a door key, which leaves me locked out of my car unless I feel like breaking into it each time I wish to even operate inside of it. So, my question is...should I just go to the dealership and get a new key? Or, better yet, how much would this cost before I give them a call and feel even more stupid? Anyways, would appreciate any commentary..maybe by someone who's had this happen before, but if any one of you would have a good guestimation on how much it'd be then that'd be pretty helpful.

Thanks.

[dead horse]

any car iv ever owned the ignition key fit the doors --