Buying art isn’t the only way to support artists, though it certainly is a wonderful thing. Something as simple/basic as sharing about an artist you like to your offline & internet friends can be very helpful too. I know of a few artists who had an entire career built on word of mouth and having their pieces passed around.
Never under-estimate the power of the smallest gesture, nor how much someone will appreciate it.
To my fellow artists I say this: some of those that people think of as “overnight sensations” are decades in the making. Be not discouraged if the “mountain is hard to climb”, the hardest struggles bring the sweetest victory.