As noted, you purchase the WiFi once at the port/onboard.
Yes, there are drink stations on the pool deck and in the buffet. Those are "free". You fill your cup (provided at the drink station) whenever you like. Sodas are also "free" when ordered in the dining rooms. If you order a soda from a lounge/bar, from a poolside server, or room service there is a charge. There are no soda packages like on other cruise lines. Drink stations have sodas, coffee, tea, hot chocolate and water.