Is there a better way?

This problem goes by various names, such as the knapsack problem, or the bin packing problem. It is a hard computer science problem. Most solutions involve using heuristics to achieve reasonable results. To obtain perfect results requires a brute-force exhaustive search through the problem space.

A perl module that solves the problem using simple rules of thumb is Algorithm::Bucketizer.

Later: a discussion of the different strategies that one can employ is shown here. The program is written in Icon, a most enjoyable language (although I haven't used it in many years).