S.!.
I have seen individual packages of apple slices in Walmart and Kroger similar to the apple dippers from McDonalds, minus the carmel and a bit cheaper.
Pretzels? My kids love pretzels and do well with that in the car. I also let them eat cucumbers (already sliced up and ready for them) and blueberries. But at 2.5 blueberries might get squished in the fingers.
Sometimes I feel like being a "nice mom" and get them Goldfish and/or CheezeIts. Also do some sort of cereal for them, usually Cheerios.
Have fun!