I know, you don't usually turn to Retro Thing for financial advice. But hear me out just this once and you could save quite a bit on DVDs of classic TV shows.
Before we go any further, I have two things to declare.
Second: My shopping style isn't exactly environmentally friendly. Follow this advice and vast flocks of polar bears will drown as the arctic warms to temperatures unseen since Sarah Palin's great grandpa hunted wooly mammoth herds on the Alaskan plains.
It turns out that many DVD box sets are much cheaper on Amazon UK, even when you add transatlantic shipping. In fact, the prices are lower than published on the Amazon site, because there's 20% VAT added to all purchases made in the UK. If you're outside the EU -- hunkered down in a little house on a mountainside in Canada, for example -- VAT will be subtracted from your purchase at checkout time.
So, all 79 episodes of Star Trek: TOS can be yours for £32.39. Shipping to the USA is £5.06, for a grand total of £37.45. That's only $60.
On Amazon.com, you'll pay $132.47 for basically the same thing (each season alone is over $60).
Pricing seems to be somewhat hit and miss. For example, The Prisoner ends up costing about the same as it does in the US, while the re-imagined Battlestar Galactica series on DVD is a bargain at only £46.64 ($80). British shows like Doctor Who can be significantly cheaper as well -- Doctor Who 2005 Series 1 to 4 can be yours for £37.19 ($60), and the Swedish sensation The Girl With The Dragon Tattoo is a bargain at £4.16 ($6.70).
Now for the big gotcha. These are Region 2 DVDs, so your player has to be region free and capable of playing PAL-format discs for them to work. That's not as big a deal as it might sound, because many DVD players sold within the past few years can be unlocked with a few button presses and automatically handle PAL to NTSC conversion. Just Google your player's model number with keywords like "region free" or "unlock." It took all of 30 seconds to unlock my player, and so far it has played everything I've thrown at it (dvdhacks is also a great resource for unlocking your player).
The other gotcha is time. It'll take a week or two for your purchases to arrive, but you weren't planning to watch all 25 Battlestar Galactica discs in a single sitting anyway.
So what are you waiting for? Extreme international shopping awaits.