Really not that much. It’s pretty easy and cheap to run a node nowadays. You either build one yourself (easy with the right tutorials) or you get one ready to go(more expensive and less learning, but fast). But i would advise option a, as it’s actually fun and feels rewarding to do it yourself.

A raspberry pi or old laptop, an sd card and 1tb ssd should suffice. Raspberry pis are hard to get at the moment, but sometimes it’s possible to reserve one by just contacting an official retailer found on the official website. This should come around 150-200€, but it’s also possible to do for cheaper. It might seem complicated to setup at first but with the right instructions like raspibolt and a community for when you need help it’s definitely doable. So not much knowledge is needed beforehand, you’ll acquire it while building and when asking questions to understand how it works.

Better privacy, you enforce the consensus rules and decide which rules run on your node and no need to trust third parties anymore. You get a whole copy of the chain, you can resist changes you don’t agree with and verify everything yourself. Helping the integrity of the network and allowing yourself to become sovereign.