I have seen many plebes report in with the Hefty cinch sack, no luggage at all. As noted above, all kinds of gear gets issued, duffle bags, etc. Luggage can always be brought during academic year, or sent to sponsor's house prior to Thanksgiving.
My son hasn't used a suitcase for coming and going from USMA, as his civilian clothes are at home. He travels w/ a bookbag that he keeps his laptop in and his shaving kit.
You probably won't need to take a suitcase home when you first get set free from the asylum. Grab a roll aboard when you go back home for Thanksgiving/Christmas and keep it in your room from that point. If you aren't a frequent traveler now is the time to learn to carry-on. You will also get issued a snazzy set of blue luggage that has the USNA Crest emblazoned on it. You get an overnight bag, a garment bag, toiletry bag. I am not sure if they still issue the satchel. When I was a 4/c backpacks were not allowed so the satchel was it. Thank god someone found some common sense.