Are cheap sub-$20 OBD2 readers any good?

For simply reading and clearing generic engine codes, budget handhelds like the MOTOPOWER MP69033 and Autel MS309 carry very large, strongly-rated verified-purchase review pools. The trade-offs are smaller screens, slower menus, and limited or no multi-system coverage. They're fine for occasional DIY use; frequent users or those needing ABS/SRS data should step up.