With orders of $25 or more, Amazon offers Prime members the DeWalt 6-Piece Spade Drill Bit Set, model no. DW1587, for $7.29 with free shipping. That's a buck under our mention from December (which didn't require a $25 purchase) and at least $2 less than you'd pay at a local retail store. This set includes the following bit sizes: 3/8", 1/2", 5/8", 3/4", 7/8", and 1".
Note that this item is offered as part of Amazon's "add-on program" and can only be purchased with an order of $25 or more.