Hi thereFirst of all, I'd recommend an Extra. There are choices too, you can get a two seat certified airplane - either a 200 or a 300, or a single seat 300S.
Costs you need to think about are: maintenance (annuals and routine maintenance. The Extra is pretty low maintenance, but there is preventative maintenance on any airplane, esp. akro airplanes. Also, the harder you fly the more the maintenance). Insurance - depends on experience level & how much the hull value is and whether or not you'll be competing or flying shows etc.; Hangar rent; fuel; oil; parachute(s); headset(s). Those are the main things.
Hope this is helpful!
Patty