Ill quote Mike Payson from electronics 101:
One interesting Scope alternative that I've been considering picking
up is the FlashyD from FPGA4Fun.

For about $220, you get what amounts to a two channel 220MHz Color
Digital storage OScope (FlashyD Rev K + Saxo). Not bad really. If
you're willing to sacrifice a channel and some speed (60MHz), you can
get the price down to about $72 (Flashy Rev H + Pluto). Several other
configurations are available between (and above) those price points.

The various options are confusing, but it's all explained if you dig
deep enough on that site (The datasheet is very helpful).
Norm