So, although I am working on getting more organized, here a couple things.
I do have all of the bubble and regular kraft envelopes, and bubble wrap in my office. Print shipping labels from PP whenever possible- in office.
I have my stash of many boxes in the basement, recycled from various places, so I hardly ever have to buy a box.
I agree with the person who said send them a "thanks for the order" notification ASAP after the order.
For thank-yous, I get tags and little cards from several other shops I frequent on etsy. I also buy cards from the dollar area at Joann's and Michael's - they are very nice cards, and usually 6 in a package for $1-1.50.
Good impressions!
I use little cello bags of various sizes to place my cards and small items, and seal them with washi tape. Every little layer of packaging says that you care!
I also have a 1/2 page little notice from my shop, saying thanks again, please come back, here's a coupon code, and how to leave a review.
Hope this helps someone else!