I know personally that I have spent hours researching suppliers for the best prices for shipping supplies, packaging supplies and materials for my painting. It is really frustrating that while one online store has a great price for some items but not others or they don't carry everything you need and you have to make lists of what each supplier has the best prices for and it is time consuming but worth it once you find them.
I now first check shipping costs since many suppliers will only use UPS or Fedex and then you get dinged heavy shipping fees and ordering across the border all the customs fees on top of it.
After a discussion with some Etsy friends, we have found a few reliable suppliers that have good prices that we want to share.
BOTTLES AND JARS
Ships worldwide except for Australia
STORE PACKAGING AND SHIPPING SUPPLIES
$15 flat shipping charge in the US
MAT FOR PRINTS, THEY ALSO HAVE GREAT DEALS ON MIXED COLORS SETS
CLEAR SLEEVE PACKAGING FOR ANY SIZE ARTWORK
Canadian and US sources
SHIPPING SUPPLIES, PACKAGING SUPPLIES, CLEAR SLEEVE PACKAGING
Canadian, US and UK shipping sites