The city of Denver is giving away FREE mulch to residents and offering compost for sale on May 4. The hours are 8 AM to 2 PM (while supplies last). The main location for this event is near I-70 and Havana, but there are several other "dig your own" sites as well around the city. Interestingly, the mulch is made from Christmas trees picked up by the waste management department earlier this year, and the compost is made from leaves dropped off at the annual leaf drop event.
See the event webpage for more information.
See the event webpage for more information.