Well you do not "Buy" a Cheque. Especially one that YOU wrote.
You write the cheque, and the bank CERTIFIES that the cheque is ALREADY HONOURED, and they did it by SECURING THE FUNDS. Their seal on your cheque SAYS SO (Certifies it). Let the mechanics of that sink in.
Printed copy · Anthology Volume 9, page 330Printed copy from The Tender For Law Anthology, Volume 9, page 330 (printed 13 June 2014). Added by this site; not part of the Facebook export.