All I have is a breadboard, some wire, a variety of passive components and ICs from HK ($20 total for tens of thousands of parts), a USB oscilloscope (eBay $60-$200), and maybe an AVR or STM32 development board. I'm overwhelmed by the number of analog and digital projects I can do, and I've been messing around with my kit for a couple years. I mostly do hobby filter design and audio synthesis.