Orenda Books have some ebooks on sale at £0.99 direct from their website, cheaper than at any of the main retailers.
They have some good crime authors, I can recommend Kjell Ola Dahl (Oslo Detectives series) and Ragnar Jónasson (Dark Iceland series) if you like Nordic Noir.
The website store is a bit clunky, I can't seem to see the book descriptions there, but the checkout and download process worked fine. There don't seem to be any georestrictions.
NOTE: Some of the ebooks have DRM, others are DRM-free. The DRM ones are only available in EPUB format and need ADE or similar to download. The DRM-free ones are available in EPUB and MOBI formats. To see which ones are DRM-free, look for Kindle in the "Available for" list.
I don't know how long the sale has been running or when it ends. It might be possible to buy the books at another retailer and price match against the publisher's website if you are in the UK.
(Edit: Beware that the DRM-free ebooks bought direct from the publisher have an intrusive watermark: your name and email is displayed at the end of each chapter. Ugh. The DRM ebooks are fine though, they don't have the watermark.)