But you see, you get more for your money with the soda. Plus, you can't take the regular drinks on rides, but you can keep the bottles. Also, the Starbucks products will probably cost more in Disney than elsewhere. Ya know, because that's just how Disney operates. A bottles soda was (I think) $4.50. Those starbucks products will probably run more like $6-$8 a piece, depending on the drink. Plus, I'm a My Coke Rewards member, so I can enter the codes and it pays back a little.
Also, I can't stand the smell of coffee. Walking into a Starbucks literally makes me gag. I'm just really anti-Starbucks. I feel like the money people spend there on a daily basis is ridiculous.
In the summer, because my family spends so much time at the pool, we get the refillable mugs. This cuts down on the cost, and I'll usually refill it on my way out to the parks. We get the two liter soda and keep it back at the room as well to help with the cost. At the water parks, we get the refill sticker.