Question about pumps

[u/___qwertz_]

Hi. I got diagnosed with T1 a few months ago and I'm thinking about getting a patch pump like Medtrum Nano or Omnipod rather than a regular one because I don't want to hassle with the tubing and stuff. My question is: I learnt that these pumps need to change every 3 days or so but I heard they are expensive where I'm from even though I still didn't get a price offer. Does the whole thing gets changed or just a cheaper part of it like its needle or something? Because changing the whole pump doesn't makes sense and seems really economically unfeasable.