This applies across basically all of life, and it's so frustrating to see people ignoring it, because what ends up happening is they use a string of 'gonnas' to justify buying stuff they don't need. Gonna get fit - buy $1500 worth of gym gear. Gonna learn electronics - buy oscilloscope, power supplies, tons of components. Gonna get your motorcycle license - buy brand new bike and stick it in the garage.
If you have a desktop computer, you're good to start. When you've done enough that your available CPU/GPU is limiting you on your own projects (not on something you pulled off github) then you can look at upgrading.
/rant
A fairly accomplished electronic engineer told me that they'd never once solved a problem using an oscilloscope, but that it helped to keep them occupied while they were mulling over what might have gone wrong. (That's presumably why the better ones have so many knobs and dials to play with, like one of those children's toys.)
Or you can use spot instances, as a sibling comment mentions - about $0.20/hour generally.
gcp: Contrary to the claims there, the CPU does matter
dsacco: yes, this will work, it will quickly become suboptimal [...] as you scale your hobby into something resembling more professional work
brudgers: I'd start with a used Dell Precision T7xxx series off of Ebay for a <$300 including RAM and a Xeon or two.
croon: If the limit is a firm $1000, I would get something like this: https://pcpartpicker.com/list/XHV9Fd