Soo... What should I buy?

Well if you just need stuff in general, get what you need anyways. A few LEDs, usually red, green, yellow, blue, ww, cw (all as different voltage level and power level ones - the wwcw only for 12V high power tho as you will probably just use them for lighting), then the matching resistors to operate the LEDs on 3V, 4.5V, whatever you need, some step down/step up converters so you can run everything on a 12V supply or a 5V supply, as you need it. Batterie holders always are a nice thing to habe, 2x for 3V, 4x for 6V plus step down converter for 5V, 8x for 12V for high power LEDs to get mobile lighting for example. Used 12V mobile supply several tumes by now to illuminate forest areas for photos and stuff ;). Then useful stuff always are potentiometers (regulateable resistors), a bunch of colored wires (red, black ofc, white, yellow, brown, blue and green-yellow are your default colors), electrical tape in different colors, different sizes drilled platines so you can easily put your planned project on those, relays/transistors. A set of different voltage/capacity rated capacitors are never wrong to have as well. If you want to then displays are a nice thing to have, some cheap lcd or 7 segment displays should be fine. Adding onto optical feedback you can get some beepers and things like that as well, there’s various frequency and voltage level ones, as well as different noise shapes in general. That’s something you’ll need to choose depending on your project though ;). Photoresistors and thermoresistors can come in useful when dealing with light so you can regulate it or with stuff that easily overheats so you can shut it down. As for processors I can recommend the AtMega series, that should fit most requirements. M3 screws are fine for almost everything, usually you don’t need bigger ons, just smaller ones in some cases when trying to get two pcbs together or sth. I bet there’s more but that’s what just comes into my mind right now. Should give you a general overview tho of what is useful when dealing with electronics :)

Oh, and don’t you dare playing with mains. Always stay with some low voltage first. USB gives you 5V at 500mA, USB 3 can even provide 5V with 2A. Get a cheap wall plug that can give you 12V 1.5A that should do most takes with no problem. Then you can always use rechargeable batteries. That’s a one time investment, I got a set of 16 AA batteries with a decent charger once for around 30€ and they’re always nice to have for everything.

As for stuff that’s not actually used in the final project but a must have (dunno if you got it already so I’ll just mention it) would be a decent dreadboard (would mean two power lines plus a bunch of space to put wires in), a good screwdriver with a decent bit set, a big and a small plier (if you only want one go for a small one first). Scissors, the wire unisolating tool (no idea how you’d exactly call it in english lol), and a high quality multimeter. That’s kinda the most important tool. I’d rather spend 10€ more on a good tool there than getting shitty results. When working with ic’s you might consider getting a pair of antistatic gloves… Soldering iron and solder are a must have anyways, if you got the money get a big and a small tipped one as well as several different sized solders. ICs tend to have really small contacts :P

Greetings

~Pepich~

LM317s 555 timers lm7085 lm78012 a box of resistors is great so you don’t have to constantly check the color coding for values MOSFETs Transistors

a cheap adjustable power supply, even better build one yourself there are kits out there where you don’t have to do mains wiring.