QR adaptor that's compatible with 501PL Sliding Quick Release Plate
 

Hi,
I want to see if any of you have used such quick release adaptor that is compatible with the Manfrotto 501PL release plate. I just purchased the Manfrotto 577 and it is compatible and works great. But it is a bit pricey and heavy.

If any of you know of a compatible one that's 1) cheaper and/or lighter, please kindly share the model and your experience with it.

Big thanks....

-Aa