I recently bought one of these:
Because I've been wanting a scope but am currently unable to drop a couple hundred to a couple thousand on one.
I bought it from Seeed Studio, but they appear to drop ship from the maker in Hong Kong, which took several weeks to get here. Now that I know this, I would instead recommend buying from here, because they stock it and are based in the US.
The scope is $50 built. It's also available as a kit for about $15 less, but it involves soldering surface mount chips and resistors, and to me that wasn't worth it. $50 for a brand new scope is a steal, anyway, IMO.
It is a cool design: it's basically 3 circuit boards mounted together with spacers. The center board has the circuit, including the LCD, and the outer 2 boards serve as the "case". It's about the size of a cassette tape, but 1" thick. For life-proofing, adding some kind of sides might be smart, since the circuitry is otherwise exposed to the elements. The functions are all labeled using the silkscreen layer of the top board. It comes with a little switch mode supply, but can use a 9vdc center positive supply, or a 9v battery if you work out a suitable adapter. It also includes a detachable probe with gator clip ends, probably pretty standard for scopes.
Performance, the part you're waiting for:
I haven't used a real analog scope. I'm guessing that those fortunate enough to have nice ones would not want to downgrade to this, but for building pedals, this is a gigantic step up from just a multi-meter. It even has a built-in oscillator, putting out a constant 500hz 5vpp square wave. This is a very cool addition and allows you to probe through a circuit without a separate function generator or plucking a guitar string over and over.
Previous reviews elsewhere complained about the screen's refresh rate being around 2-3 fps, but this has been significantly upgraded. It's still not instantaneous like a more expensive scope should be, but it's generally around 6 frames per second. Certainly good enough for my purposes (tweaking pulse width trims, that kind of thing).
The bandwidth and screen resolution are perfectly usable for audio, and I would think probably still usable beyond that (1Mhz). Of course, you can change the time scale and level sensitivity, vertical and horizontal position, etc. It's also got a frequency counter. Max input voltage is 50v, so fine for stompboxes; I don't know what the actual audio voltages are in amps, so I don't know (but kind of doubt) that this would be usable there.
I wanted a little handheld scope for peering more deeply into circuits, seeing what exactly each part was doing so I could get a better understanding of electronics. I also wanted to be able to debug with greater clarity than an audio probe, and to be able to see oscillator waveforms to tweak the more precisely. This scope does all that perfectly. Although I love old equipment, and having an old analog scope would be really neat aesthetically, at this point I'm not sure I have any real technical need for anything beyond this JYE scope.