Todd, I sell powder tubes but they only hold up to 80gr of powder.
muzzle-loaders.com for one sells a bunch of supplies for todays inlines.
even ebay sells muzzleloading supplies, sometimes at a higher cost however LOL. Search around, you will find lots of places.
What rifle are you shooting? We can whittle down the list of what you actually need VS crap folks tell you that you need.