That is a terrible learning environment. Our profs always leave a box outside the laboratory with free expired textbooks, partial part lots, and damaged/old test equipment.

Some people get into Science, Software, and Electronics for the wrong reasons.. And end up miserable teaching after failing in the private sector.

A few 555 can teach people a lot, and burning out parts is part of the learning process. Most fold the DIP legs under like a "dead bug", as that is the tradition to prevent its accidental re-use.

In terms of component cost, ATTINY or PIC10 mcu have internal RC oscillators with configurable PWM pin hardware. Thus a single component is usually better than the accumulated precision error in discreet parts around a 555.

I usually recommend an RC car/truck build, https://eater.net/6502 , and or an LDOmotors Voron kit. Getting your Ham Radio technician license will also introduce you to an intuitive understanding of EE component model limits.

This covers a lot about discreet analog circuits, and I recommend trying to figure out how every circuit works on your own:

https://archive.org/details/encyclopediaofelectroniccircuits...

Simulators are not perfect, but they are a lot cheaper when starting out. =3

Tutorials:

https://www.youtube.com/@FesZElectronics/videos

Tools:

https://www.analog.com/en/resources/design-tools-and-calcula...

https://web.archive.org/web/20200218212700/http://spectrum-s...

This requires a GPU on Windows, but is a more advanced newer Spice simulator:

https://www.qorvo.com/design-hub/design-tools/interactive/qs...

Doin' It with a 555: One Chip to Rule Them All