The first advertisement, "Buy two bottles of soda and get one soda free," seems more reasonable. This type of promotion is common in retail and makes sense as it encourages customers to make a purchase while providing a small incentive.
On the other hand, the second advertisement, "Buy two bottles of soda and get a trip to Disney World," is much less plausible. Such a promotion would be highly expensive for the company and is unlikely to be feasible. It raises questions about the validity and sustainability of such a promotional offer. Therefore, the first advertisement is the more reasonable one.