Hello, bit of a noob here - but a very invested noob 
I’m currently on photoshop as I feel two starbucks coffees a month for the developers is fair for the app and liking it so far. Anyways, as others pointed out, for ipad definitely procreate, I have it as my mobile art app and its pretty awesome not to mention super affordable (tablet not withstanding)
As for other apps on PC/mac I can recommend clip studio paint and corel painter (goes for heavy discounts every now and then in bundles over at the website humble bundle and is a one time purchase). As said before bit of a noob, got both of them through discounts to play around with before I joined here and started the digital art course
From. Y very limited experience what I can summarise from the experience is that painter has a metric ton of painting and drawing tools with fancy blending that simulates real life but the actual brush stroking feels weird, like bad performance but probably just is that way. Its not laggy but feels slow, sticky I dont know (this on a beefy rig)
Clip studio seems more promising to me, lots of little tools that help digital artists to make your life easier, but im avoiding thise for now as they could become a digital crutch or shortcuts I shouldnt take until im more advanced. Also, its emulates real media with its brushes and i couldnt find a simple round hard or round soft brush for example, so maybe some more getting used to the UI
Krita is free but I haven’t really tried it out well XD
Photoshop personally so far seems much more intuitive. Just my two cents
Cheers
