Starting July 1st, retail stores in Denver will be required to charge $0.10 per carryout bag. You can avoid the bag fee by bringing your own bags. The ordinance does not apply to bags used to package bulk items, produce, or meat. The charges for the bags will have to be displayed separately on customer receipts. Portions of the bag fee will be kept by the store to cover the cost of implementing the program and by the city to address the impacts of disposable bags and single-use products. Starting now, while supplies last, the city will give away reusable bags.
More info here