Make your own 50mm wide bias binding with the Clover bias binding maker. 
Cut a strip of fabric. You can find the right with of the strip in the user manual. Insert the strip in the maker, place your iron on the end and pull the maker backwards, following directly with the iron.
This 5 cm wide bias binding maker is great for making quick and easy waistbands. First add interlining to the strip of fabric, then pull it throw the binding maker and sew on...

Available in 12, 18, 25 and 50mm. This version is black/silver, the other witdhs have a different color.