In many cases oscilloscope is used to test low voltage and low frequency signals. This is what any low end oscilloscope is capable of. I think that proper oscilloscope should be on every hobbyists bench. But still there might be various reasons not to have. As quick fix to this problem might be a DIY solution. Tomeko have build really minimalistic scope project on STM32F042 ARM Cortex microcontroller. It accepts single channel, single voltage range signals and streams it to PC via USB FS with libusb as driver.
Scope’s sampling frequency is 480kSps at 8-bit resolution. Signal is captured in real time Windows application which can record signal to file up to 512M samples. This is enough for simple measurements and monitoring. The great thing about this is that circuit is really minimalistic with only few passive components on it. Because of this simplicity, it will never replace any oscilloscope, but it could find its use simple signal debugging is required. In other hand it can serve as additional module in some project where you might want to have a clue about signals inside. If you build it with home technologies it becomes really cheap.