It appears that there are some great suggestions of bike. I assume that 90% of them would be out of the price range you would like to be in.
I started on a Honda nighthawk 650sc. It was a great bike. I purchased it for 450 put 200 in to it and rode it for 2 years with no problems. The 650 motor had plenty of power and the riding position was comfortable. I still have it in my garage. I can't bear to part with it.
I then went in to a 98 Yamaha yzf600r. Another great bike, had the power (after some mods), sport bike styling and performance but a more comfortable ride. My ass was not above my elbows on it. I rode with guys on R6's, CBRs and GSXRs. I never had problems keeping up. A good used one will run about 3000.
I did eventually trade it in on a 96 Kawasaki 800 classic. I love the Kawasaki. It is very comfortable to ride. I commute 50mi. a day on it and love every minute. You can get in to one for about 3500.00.
I understand being on a budget. The wife would only let me get a bike if I could pay cash for it. That is why I started with the Honda.
No matter what you ride, the only important thing is that you are riding.
Keep the rubber side down