I don't do raids often, but I've been buying the event boxes for the cheaper items - The Star Pieces primarily.
However, these all come with Premium Raid Passes. This would normally be fine, but I don't raid very often, and even when I do, the free passes are the only ones that get used, since once I've used it, the very next time I join a raid battle, or visit a PokeStop, I get another free one anyway.
Edit: currently, even if I do leave a raid, I am immediately rewarded with another free raid pass.
At this rate, they're just taking up space in my bag. Is there any way I can get rid of them, or even use them?