Rather than having strict minimums, we have benchmarks at which point shipping is free. If those benchmarks are not met, we are more than happy to send your order, we just pass along a portion of the shipping cost ($10) to help cover our butts (we'll cover the rest of the shipping cost).
As for the Free Shipping Benchmarks, those are determined based on where each brand is shipped from. Most brands are shipped direct from the STOCKED HQ here in Seattle to you and come with one, combined free shipping benchmark. However, to help save on final costs for certain brands, there are some that we have shipped direct from them to you. That is, rather than having them ship product to us and then back to you (i.e. 2x shipping), we just have them send it direct to you (1x shipping). Please refer to the details below.