Someone still bears the costs to produce, transport, and stock it. You only save them the credit card processing fee (or the cost of handling cash, or similar) by stealing it instead of buying it. Even if they have insurance, insurance very efficiently charges the statistical average risk (plus overhead and profit...) to the purchasers of their insurance. Higher theft results in higher insurance costs.

If you want lower cost nylon clips, consider 3D printing, especially if you know someone that already has a printer. Because the filament can be transported quite efficiently, the environmental impact may also be substantially lower, especially for small items.