Define economical.
I got a 12 volt Do-All Arial Assault 3.0 (because it throws targets a little harder) and a wireless remote, and am very pleased. I can get any target presentation at any range.
The various manually operated traps with a string release work, but you are limited to going away shots, and I have found with the stick in the ground models unless you stand on them, or bolt them to something solid, they will work the hole in the ground loose and lose a lot of impetus to the targets. There are lots of choices in between the electrics and the foot models, including ones you sit on and ones that fit in a receiver hitch. They all throw targets, but what you can do with them is different.