Factory wholesale A3 A4 A5 size eco friend packing material corrugated paper mailers envelopes bags

Hello, I am looking for A4 customised paper envelopes. How much for samples?
Seam:2 sides protection heat seal
Application:Document,Cosmetics,Post Office, Stationary
Sample policy:Free for existed sample, and pay for customzied sample
Feature:Eco-friend, Easy Recycled, Protective, Easy ink
Printing:custom made 6 colors available
Certificate:ROHS/ISO9001:2015
Usage:Delivery Package
Logo:Customer's Logo
MOQ:10000 Pcs
Color:Mixed Color
Place of Origin:CN;GUA
Material:Customized
Brand Name:Beta