With a low budget, if you are ok with lower resolution and restricted arm64 app (universal, 32, arm are ok) compatibility then you can consider buying a used $30 samsung 10.1 gt-n8000 with a built in stylus and flashing a cusom rom on it like LineageOs. You might find that doing so can save you money until you can afford an ipad + pen + keyboard set. Without flashing a different OS on this particular device you will be blocked from connecting the the samsung website by the manufacturer, and blocked from establishing a connection for installing playstore apps so if you go this route you will 100% need to do extra work replacing your stock OS.

Flash custom 19.1 lineage custom rom from xda forum and if you need google framework stuff and apps (you can just download playstore and apk from apkmirror without this even) whatthegapps 12.1 is compatible with the rom.

To install the rom you need LineageOS 19.1 (specific to gt-n8000 from the developer on xda, he's done a lot of different releases), odin 3.1, there is an app for reading the device drivers you will find it on many diff youtube tutorials, TWRM, and the whatthegapps 12.1 if you want google services (advise against gapps, just download apk's off google manually and use web email, they will notice your access to their services on an outdated device and require mobile otp its a headache so if you only flash the rom you will be even better than complicating things).

Once you have the device running on a new OS, you can use it like any android tablet with a built in stylus. Some drawing apps do have a bit of delay in latency when using the stylus, others not. Some new android apps require arm64 which is not always installable, but many others are labelled as universal on apkmirror. The device supports bluetooth with lineage.