For a limited time only, Toys R Us America will be offering “$5 for 2” on ALL LEGO Series minifigures. Mix and match however you like! This is valid in-stores and online. However, for online purchases, it is limited to only 1 discount per order. Thanks to forum member minifigW for the heads up.
Selection varies by store. LEGO Series minifigures that they still currently carry include Series 12 and 13 as well as Simpsons. Though, it may be a bit more difficult to find some of the older series minifigures.