Before comparing plans, figure out how much data you actually use. Both iOS and Android track cellular data usage in settings, and Reviews.org's guide on how much data you need walks through exactly where to look on both platforms. The key is checking the past three to six months, not just one heavy month. Most students who do this audit find they're using far less than their unlimited plan implies — often somewhere in the single digits of gigabytes, despite paying for premium tiers built around 50GB or more.
If your usage is consistently under 15GB, a metered plan in the 5–20GB range will almost certainly save you money. And you can push your usage down further with a few habits that cost nothing. Pre-download playlists and podcasts before leaving your dorm, save video calls for Wi-Fi, and let campus networks handle the heavy lifting. Guides like Xfinity Mobile's student plan breakdown make a similar point — for most campus life, "unlimited" is overkill when you're already covered with Wi-Fi.
That said, there are some reasons to keep an unlimited plan. First, unlimited plans often include higher priority data during network congestion, which matters at football games, concerts, and anywhere else thousands of phones fight for the same tower. Second, if you regularly tether a laptop or stream HD video away from Wi-Fi, you can blow past a metered data cap fast. If either of those describes you, downsizing your plan isn't the move. For everyone else, it's probably the single biggest saving tip on this list.