If you don't use labels how will you track your package if it gets lost? Delivery confirmation costs .95 at the post office and is free if you print labels from etsy.
You pay .90 for comfirmation at the PO. It is free when you print on line. and it is so nice to have all the information on it when you get to the po or drop box/
Do you not have a printer?
It would be the best investment you could make.
The post office doesn't package items for you. Shipping is easy once you do it a few times. I'd package myself and take to the post office until your ready to ship on your own.