|Dual Channel Oscilloscope and waveform generator|
It can be found here and there are some videos of it in operation here.
The waveform generator operates independently from the scope function so you can apply the signal to a filter circuit and watch the results on the scope.
It's also possible to write your own software and use it for other projects, there is one picture on the site showing it displaying temperature from a DS18B20. I think this requires a special programmer though.
All for a price of $49, a bargain!
I don't know about availability in the UK but If anyone sees it for sale in the UK please make a comment.