There are cheap fixed wing microlights - the Thruster & MW series for instance. But although they would be easier to fly in bumpy conditions the Thruster, in particular, being a brake-less tail dragger would be no better off than a flexwing on the ground. The main advantage of flexwings is the ability to quickly remove the wing, and with a bit more time fully de-rig it. This can greatly reduce hangarage requirements. Many folk trailer them home and store in the garage.