You could try things out with a Platinum Preppy for about 5 USD. Past that, a Pilot Metropolitan, or a Lamy Safari would be good entry level pens, in the 20 USD range. For 100-200 USD, you can get a very nice pen like the Pilot Custom Heritage 912, or a Pelikan M200. I'd recommend trying out the cheaper options first so you get an idea of what sorts of nibs you like.

http://gouletpens.com

http://jetpens.com

http://nibs.com

Are decent places to start looking for more modern pens. Hope that helps.