I was in the same boat as you not long ago. Before I started at my church there was a full meal provided at youth group, so that was the expectation. I slowly backed it off because it's just too much work, costs too much money, and takes too much time away from what else we could be doing with the night.
For snacks I've asked parents if they could donate non-perishable snack foods that we can keep on hand, so mostly we get chips, salsa, packaged cookies, etc... plus some freezer stuff like pizza rolls. Seeing as that's totally unhealthy, though, I also try to pick up fresh fruit or veggies to go along with it so that the options aren't all just junk.