Part of the issue is small numbers like you currently have typically don't get "group rates." This is especially true at hotels. If you are also looking at a charter bus, that is a fixed cost no matter how many people ride. Empty seats still cost $$

We (CCIS Travel is the company I work for) did a South Padre trip for a school group around San Antonio a few years back. They had a great time, but you also MUST consider that weekends at South Padre in March and April are PRIME time to go. Supply and Demand will drive up that cost. There can also be some behavior that might not be "high school appropriate" happening in South Padre around that time of year as well.

Planning it yourself is possible, obviously, but one key factor in using a tour operator is the liability coverage they offer. Remember, the person signing on the dotted line is the person that is going to get sued if something goes sideways. An accident, or damage to property........ Will your school back you (financially) if you don't use a tour operator with liability coverage? That would be like being in the classroom without the TMEA coverage or being a member of ATPE.....

Happy to help if you want to reach out. martin (at) ccistravel (dot) com