It's possible to run a node in pruned mode, where you set the amount is space which is used by blocks. Older blocks are then pruned to stay within the space limit. You can run a node in this way for $5 a month.

If you support Bitcoin, much in the same way as people support many open source projects, this isn't a lot of money to fork out. Compared to the amount of time contributors spend writing software for free for the good of the world.