The Ruger 10/22 is an excellent platform to begin with. There are so many configurations to choose from so you can "tac" it up any way you want from a sniper style with a bull barrell to one with accessory rails and ajustable stock. Price, even after any accessories or replacement stock, would be within your range. Most if not all modifications are simple enough to perform on your own with alan wrenches and a screw driver so it also makes a fun project. That being said I would also say the other posts so far are great advice too. Just depends on the style and exactly how much you want to spend and if you want to turn it into a small project.
Have fun deciding!