I was under the impression that redscale film is simply regular C41 colour film flipped around in the canister, so that it loads the opposite way round. This means (as I understand it), the red layer(s) get more light than they normally would, and the picture comes out looking quite red.
You can check out Redbird by Rollei too, for a rescale film. However, in the UK, Fototo does 3 rolls of Redscale for less than £10, which is OK with me.
Lomography themselves sell Kodak and Fujifilm films for atrocious amounts of money, and their P&P is through the roof. Their "own brand" films are not too badly priced though.