Food The best Cuban food I've had so far in Orlando is at the Black Bean Deli. I like to get the lunch special, which includes half a medianoche (classic midnight Cuban sandwich) and a cup of delicious black beans and rice ($5), a side of sweet plantains (maduros - $2.30), and one of their imported Latin American sodas ($1). Also, papas rellenas (filled potato dumplings - $2.75 for two) are just delicious in general.
Dessert Although I've never been to Seven Sisters Coffeehouse, after reading the reviews it's definitely on my list. Taste their selection of cakes, cupcakes, coffees, or teas.
Total Cost for lunch, dessert, and an outing: $12+ (although you probably won't leave Grandma Party without buying something)