The advertisement that seems more reasonable is "Buy two bottles of soda and get one soda free." This promotion is a common marketing tactic used by many retailers, and it makes sense within the context of a consumer beverage purchase.
In contrast, "Buy two bottles of soda and get a free trip to Disney World" is an exaggerated claim that is unrealistic and highly unlikely. Offering a trip to a major theme park in exchange for the purchase of two bottles of soda is not a standard or plausible promotion, as the value of a trip far exceeds the cost of the sodas.
Overall, the first advertisement is more believable and aligns with typical buying incentives.