Standard supply pack

For todays mission I need 2 of them. Never heard or seen this item before so I am not sure where to even begin to look for them. Any hints??

Spiral Wikipedia is your friend.
http://wiki.spiralknights.com/index.php?title=Special%3ASearch&search=su...

Huh? My Prestige mission said COMPACT supply kit.

As you rank up, your tier also goes up. As you rank up into higher tiers, prestige missions makes you dive in the tier equivalent of the rank. It isn't one tier per rank, but after a certain rank you are of a certain tier.
So your supply delivery requires more expensive supplies.
This also applies to monster research and arms appropriation. Geo surveys might have an increase in minerals required, but I haven't had a chance to see that.

Don't bother with the mission. All you do is click the start mission button, the "supply packs" are removed from your inventory, and then you get your prestige points. You don't actually deliver anything anywhere.

Is there a purpose to these supply packs other than satisfying the missions?
I completed several missions wherein the objective involved delivering supplies. I had no supply packs and succeeded by standing on the appropriate spot and clicking the attack button.
I like to have one of each material in my inventory (still looking for a zee core). Am I going to have to keep buying these stupid things for no other reason than to replace them when missions deplete them?

You were talking about the salt delivery? That took nothing from your inventory. The supply packs sold by vatel only fulfills the missions specifically asking for supply packs. That is part of the non combat prestige missions.

Standard crown-sink pack would've been a great name too
Vatel of bazaar.