As of spring 2015, all four seasons of "Once Upon A Time" are available for streaming on Amazon.com and iTunes. Both iTunes and Amazon.com label each episode clearly with a season and episode number and original air date.
The complete first three seasons of “Once Upon a Time” are available for purchase on Amazon.com and iTunes, with episodes from the fourth season released for viewing within 24 hours of their initial network broadcast. Individual HD episodes are available for purchase on both iTunes and Amazon.com for $2.99 each, while full seasons range from $19.99 to $39.99. Amazon.com also offers the show for streaming in standard definition for $1.99 per episode or $14.99 to $34.99 for a full season.