it all depends on your resources and or your willingness to learn something new.... like bike mechanics.

you can really build a fixie for next to nothing provided you know some peeps willing to donate and/or have a frame or can acquire a frame. A local bike shop or LBS as you will see on the forums that caters to used parts is a great place to pick up the essentials for piecing together a fixie, here in PDX its City Bikes. You can acquire all you need for piecing together whatever monster you wish to devote time to create.

For starting out on a fixie you might want to use a brake if you arent completely comfortable with the idea of no brakes, it WILL HELP YOU STOP quicker in emergencies.

And really it all comes down to "how much you are willing to spend" and if you want to go the cheaper route "how much time you are willing to devote"

my first ss was a converted '83 univega roadie that I toke over from my dad, then I got into fixies, my latest build I got from John at businesscycles.com nice guy and will work with you on any request you might have. Other than the internet route I would really recommend talking to your local wrench gals/guys.

edit: I've been drinking alot so I appologize for w/e