The organization that I'm most familiar with is
Friends of UMass Fencing (FUMF).
Money is collected via annual dues paid by members of the BoD, periodic fundraisers (usually combined with social activities), mostly-unsolicited donations, etc.
Money is used for meetday food (as mentioned), equipment purchases, some team entry fees (PdT, Nationals, as situations warrent), and building a long-term capital fund.
There is a BoD that meets 3-4 times annually to determine direction for the organization and to allocate spending.
FUMF publishes their own newsletter which gets sent to the current team, parents of the current team, and all FUMF members (membership is free). Alumni get that good feeling from being able to help give back to the organization that, presumably, meant so much to them for four (or in many cases, five or even six) years. Newsletter is quarterly (roughly) and distributed electronically (used to be hard-copy, but that gets expensive when you have a longish mailing list and free membership).
The other similar organization that I've been involved with is the alumni support group for Hopkins Fencing,
Blue Jays Unlimited. Organized as a part of the overall athletics support for the school. Each team has their own account and people responsible for spending decisions. Standard university solicitations for annual membership at a variety of membership levels. Money is used for long-term largish projects and for gifts to graduating seniors (school blanket).
-B