Costa coffee have possibly the worst loyalty card system of all the coffee shops. You get 5p worth of store credit back for each £1 you spend, so essentially 1 free coffee for each 20 or so cups that you buy, which is about twice the number required by anyone else. Admittedly you can spend the credit on anything, but it's still not that great. However, they recently started selling their coffee for home Tassimo machines, and as a promotion offered me a machine which retails at £120 (market price £80-£100) for £30.
I've never been a huge fan of the idea of pod coffee machines. The pods vary between 20p each for standard coffee, to 65p for a latte, so they are pretty pricey. Last year, my second Gaggia espresso machine died and I can't afford to replace it, so regarded as a mechanism for cutting down my coffee shop spend, even at 65p a cup, the £30 cost of entry suddenly made the whole thing a lot more appealing.
The best thing about the Tassimo is that it's the easiest, cleanest coffee machine I've ever owned. You put the pod in, press the button, and you're done. The least good thing about it is that you're stuck with whatever pods Kraft feel like producing, and it's a closed system, so there's no competition on price. Buy the T-Discs from Amazon or the local Tescos, you will pay the same for them. While there are a number of latte style drinks provided, they use Kraft's UHT condensed creamer, which, although pretty acceptable for that sort of thing, is only available with sugar, and, well, still isn't as nice as ordinary milk. I can heat milk in the microwave, but none of the local stores sell a stand alone "espresso" pod, which makes life difficult (at least for first world values of difficult).
Here comes the nerdery. I just wanted to write this down somewhere before I forgot it. If you do not care about Tassimo coffee machines and how to hack them to get around some annoying restrictions, then you won't be interested in the rest of this post.The interesting thing about Tassimo is that the brew program is dictated by bar codes printed on the top of the pods. There is a bar code reader inside the machine, which translates the bar code into temperature and pressure settings. It's all documented at http://blog.chapmanconsulting.ca/wiki/Tassimo%20Hacking.ashx.
I have a label printer (a brother QL-560LE) which prints sticky labels, and can print bar codes on it. Sure enough, a little experimentation shows that the bar codes on the pods are I-2/5 standard with a checksum bit, and that setting the printer software to generate them at medium size with a 2:1 aspect ratio produces a 34mm wide bar code, which appears to be the right width and can be read by the Tassimo machine.
Armed with this knowledge, I was able to scan the lid of a Costa Cappuccino coffee cartridge (i.e. one designed to produce espresso style coffee to be mixed with the creamer) using my phone. The code for this cartridge is 063050. The label printer was very happy to produce a 60mm odd high (the width of the printer) sticker with this bar code on (and a small text label to say which bar code it is). This can then be trimmed with scissors and stuck on to any cartridge. Sure enough I can now brew "espresso" using any base coffee cartridge, and make it into latte with the use of microwaved milk. It tastes, if not as good as the best cup of coffee I've made with an espresso machine, far far better than the worst one.
(The file for the P-Touch labeling software can be found here.)