Do you need that item? If the answer is yes, then ask yourself if it is something you can buy at a store locally? If ordering online is the best option, then opt for store pick-up if purchasing from a store within your area. When feasible choose items made from recycled content and has minimal packaging.
When ordering from Amazon choose the no rush option. By choosing the no rush option your order is more likely to arrive in a box appropriately sized for your order, and multiple items will be combined to reduce the number of packages being used. Also, if it is offered choose the “less packaging” option.
Be creative! Explore your different options before you make that purchase. Is it something you can buy gently used at a local thrift store or rehomed from your social network? What about borrowing it from a neighbor or family member if it is something used infrequently? If you are on social media join local buy nothing groups to see if someone has that item you want.