That's one I hadn't seen before.
For just a 24MSPS 8ch Logic Analyser protocol decoder, then there's been some very cheap ones, like these:
https://www.sparkfun.com/products/15033
Although boards to send SPI/I2C are slightly more and GUI software may be lacking on cheapest FTDI MPSSE & Bus Pirate etc. ones (but significantly cheaper than the quite popular Total Phase Aardvark etc.)
And multi-instrument in one types are often quite a bit more.
These Discovery ones, with 100MSPS sampling are around twice the bitscope price for just Digital inputs. But do seem quite good, apart from not being very open with their design, to allow you to write all your own software.
And ones with Analogue inputs are quite a bit more:
https://store.digilentinc.com/test-a...al-generators/