It is just a little challenge, but it is part of what makes running the bookstore fun.
You may have seen the Postal Service ads for their flat rate Priority Mail packages. Whatever you can fit in one of their flat rate mailers is shipped for a single price. It is not dependent upon weight.
We use Priority Mail almost exclusively with our sales on our website. The industry standard traditional shipping pricing has been based on weight. Each item has a weight, add the weights together and calculate the shipping charge by weight. For the past several years we have been using a simpler method, counting the number of items in the order. The first item costs a specific amount for shipping, and each additional item is added at a reduced amount. Books are weighted more in this scheme than are non-books because books generally weigh more.
This past week Nancy and I have been figuring out a new way to calculate shipping charges for our web customers. It is based on volume. What can be shipped in each flat rate mailer is not based on weight but on volume, so we have been devising a method of determining each item's volume and replacing our current shipping calculation with this new one. Yesterday, as we neared the completion of this new method, I remarked to Nancy that the process was like inventing a new wheel. In her wisdom she replied, "You've seen the ads. Many businesses must be changing their shipping from weight-based to volume-based. Trucks and airplanes have figured out how many packages fit in a shipping container. Volume matters more to them than weight." We are not the only business that is, or has, changed their method of calculating shipping charges.
FYI, we are not measuring the specific volume of each item in the store in cubic inches or any other normal unit of measure. Our unit of measure is a flat rate mailer. If a flat rate mailer will hold a single volume, like a bible, then that item's volume is One. The same flat rate mailer may hold four smaller paperback books. Their volume is then 1/4. And, at the extreme end, 50 decals will fit in a flat rate mailer so their volume is 1/50. We have larger numbers for big items. One big object might be a Three, for instance (No, we will not cut the large item into three pieces to mail it!).
It's been challenging and, therefore, part of what makes managing this-ministry-which-is-the-store fun.