My husband’s family in Texas does sponsorship. For example one family will sponsor the cake, another the band, etc. for his niece’s quinceañera we sponsored the cake. For his sister’s wedding we sponsored the mariachi band. When we attended, each sponsor received a flower to wear to be recognized. Sponsoring doesn’t mean you pick those items out. We told them what we would sponsor and they picked their own cake and band and we paid for what they selected.
Here in Tampa the gifts my daughter gave at her friends’ quinceañera were no different than any other birthday party.
My husband had a niece who didn’t want a party. She wanted to go to Hawaii with her best friend (escorted by mom) so asked for sponsors to help pay for the trip. That was pretty much just donating to their vacation fund.
Sponsorship does help with the cost. My daughter decided not to have a quinceañera since our family is split among so many different locations and if we went to Texas to hold it where the majority of her Mexican family are, her friends wouldn’t be able to attend. However, all of those families that WE sponsored, it would go without saying would be expected to sponsor back when it was our daughter’s quinceañera or wedding. Right now my daughter is trying to decide what she wants to do for her 16th Birthday. Disney or a cruise with her bff is the debate. LoL.