Like Bugnut, I'm assuming you are looking for an old air-cooled Beetle, not a New Beetle. Is that right? Do you want it for a second car to cruise around in, or are you looking to have it serve as your main mode of transportation? Do you think you would be interested in learning to do some of the general upkeep on it yourself, or do you just want to drive it and pay someone else to service it or fix it if something goes wrong? These old bugs are "high maintenance" compaired to modern cars, but fortunantly, if you're on a tight budget and don't mind getting a grease on your hands, almost anyone can learn to do the bulk of the regular stuff like changing the oil, adjusting the points, adusting the valves, adjusting the timing, etc.
Finding a really nice bug that doesn't need much for under $2500 is getting tougher every day. You'll run across one every now and then, but not every day. If you're looking for a pre-67 Beetle in that price range, you won't find many that don't need some work. You're best bet is to look for something from the late 60's or the 70's . . . stick to a standard Beetle if you can, but Super Beetles tend to be a little cheaper. There's nothing wrong with a Super Beetle for a daily driver, IF you have the front end right . . . but the slightest problem can cause the famous "Super Beetle Shimmies" between 45 and 55 MPH.
As for an automatic or manual, Beetles didn't come with full automatics, but from '68-74 . . . or maybe 75 . . . they had an "AutoStick." The Autostick had to be manually shifted, but the clutch worked automatically . . . plus it had a torque converter so you could stop and start in gear like you do with a modern automatic. It was sort of an over-engineered system and most VW mechanics hated them . . . over the years, when they gave problems, most got tossed out and replaced with a manual tranny, so finding one in good working order today is pretty tough . . . there are still a few out there, but again, they are getting harder to find every day.
Check out the one over at R & M that Bugnut referred to. I think it's a pretty nice bug . . . he started out asking over 3K but he needs the money quick so he's dropped the price down to the top end of your price range.
http://www.volksfolks.org/forums/viewtopic.php?t=5408