Two factors explain the price differences between models.
First, size: the Large model requires more materials and manufacturing work than the Medium, which is naturally reflected in its price.
Then, the fabric: each Bloon collection is made with materials that have different characteristics and production costs. Some fabrics are rarer, more technical, or more demanding to work with, which impacts the final price. This attention to material selection and craftsmanship makes all the difference, both in the feel and in your interior.
In all cases, whichever model you choose, the benefits for your body remain exactly the same.