There is a much cheaper way, although those bird lauchers work amazing, my sponsor has both the large and small one and they are great, but expensive.
The cheap way is dig a shallow hole in the ground, but quarry in it. Put a piece of ply wood over it. Attach a stout string to the board. run the string along the ground to a pivot. A simple stake in the ground will work. Run the string around the pivot and then at a square angle, attach it to another stake, effectively making a trip wire.
Run your hunt as normal and when ready to flush approach the trip wire. Stepping low you will be able to step into the trip wire which will pull the board covering your quarry away from the hole. Quarry sees opening and bails for it.
Obviously it doesn't work as well as a spring loaded game launcher, but for those wanting a simple way to do it, and not willing to pay for one of those, this will work, i have used it and it works great. If the quarry doesn't come out immidiately, just keep walking. If needed turn around and walk back towards the hole and rap it with your flushing stick.