When starting out with your eBay business it can be a challenge to find enough supplies to get get everything shipped. Buying tape, boxes, poly bags and bubble wrap in bulk simply doesn’t make sense when only a few orders are going out a week. There’s a ton of that stuff just laying around or being thrown in the trash, is that cool to use? Of course it is, but learn to grow out of it as soon as possible.
Boxes
Reusing boxes is fine as long as they are totally clean and still structurally sound. The last thing you want is for a customer to complain that something smells or the box fell apart during shipping.
Boxes have a seam along the vertical size that will allow you to break it apart and turn it inside out. I do this whenever I have an Amazon box or anything else that is heavily branded, While I appreciate the free box, I don’t want to give any free advertising to another company. Be sure that the re-taped edge is strong before sending the package out.
If the box simply has labels on it, use a Sharpie to scratch out addresses or bar codes, Give the post office as few options to screw something up as possible. Put your label on top of any that are on the box to cover them up.
Do not use any boxes from food or any questionable sources. Diaper boxes are super durable, but some folks might feel weird getting that kind of box delivered at their door. Food boxes are non-negotiable Do no use them.
Packing Supplies
Reusing packing supplies is fair game, Bubble wrap is incredibly expensive and just shows up in packages you get. I save everything that I get in a plastic tote and bust it out as needed.
Dumpster diving for packing materials works too, but you have to be 1000% certain that it is all clean enough to use. You’re literally getting paid to ship someone trash.
The Long Game
You’re trying to build a business, and in the process have to become more professional at every opportunity. With some experience nearly all of your shipping needs can be done with just a few different boxes and poly mailers, which you can get cheap or even for free. Presentation matters, and if the first thing your customer sees is an Amazon box from their eBay purchase they may not be the most confident in their purchase from you.
Use what shipping supplies you have at the moment, but work to deliver professionally packaged every time. That kind of presentation sets the stage for the awesome stuff you sold them inside the box.