For anyone curious I ended up getting this three in one that also acts as a signal generator. I'm gonna be doing some basic signal processing for an EMG HID project so it'll be useful to test whether my FFT captures frequencies accurately enough.

https://www.aliexpress.com/item/1005005202074391.html

@mauve i kind of forgot but you can actually use :
https://xoscope.sourceforge.net/
with an audio cable to detect signals but i think you have to have a resistor on either the positive or negative.. dont go doing this willy nilly but it is at least interesting that you can :)

@mauve
I can't recommend particular kit but I think voltmeters are more commodity, so not a big deal, and for oscilloscope I would look at PC based oscilloscope i/f's if i was buying.

Back in about 1980 I asked my Physics tutor if I could borrow an oscilloscope and he took me to the stores, found a massive Tektronics scope and said here you are, it's yours. I couldn't believe it. A few years earlier I'd tried to build one from a magazine but wasn't quite up to it but learned a lot.

Good luck.

@mauve I got one from AliExpress. It's the Zoyi ZT-703S which is a multimeter/oscilloscope handheld combo.

Two channels at 50MHz I think. Only briefly played with it for a week or two but seems to do the job.

@mauve There's a brand FNIRSI that make things like a really good & well reviewed USB tester (https://fnirsistore.com/product/fnirsi-fnb58-usb-tester-voltmeter-ammeter/) that I use and they seem to some some decent cheap oscilloscopes
https://fnirsistore.com/product-category/fnirsi-oscilloscope/
(The USB tester includes oscilloscope for the USB power).
See also https://hackaday.com/2023/05/11/fnirsi-vs-rigol-an-alternate-view/ ("it's not perfect but it's decent enough for all the more common uses")