As we previously posted that Amazon has bought the exclusive rights to stream future releases of Downton Abbey, a check of the PBS website reveals that the last episode of Season 3 has just expired on 3/03/13 at 11:59 PM ET (This was a link to Season 3 Episode 7, but is now gone - clicking "watch online" on PBS.org now shows only a single episode of "Page Eight" available.). Seasons 1 and 2 are also no longer available on the site.
Seasons 1 and 2 are available for free on Amazon for Amazon Prime members in both regular and HD, but Season 3 is $1.99 per episode for normal, and $2.99 each for HD. This means that, unless you can find reposts from people who pulled Season 3 off of PBS.org, your only option is to buy it from them, or wait until Amazon makes it free with Prime - possibly when Season 4 aires in September 2013. If you do decide to buy Season 3, be sure to buy it all at once for $14.99/$19.99, currently saving you $2.92/$6.92 off of the regular price.
Downton Abbey Amazon links*:
Season 1: Normal, HD - free with Prime
Season 2: Normal, HD - free with Prime
Season 3: Normal, HD - $1.99/Ep, $2.99/Ep HD
*Links to Amazon Instant Video are affiliate links so that Amazon knows we sent you. It doesn't cost you anything extra and we appreciate you letting them know we sent you.