@phunkeesea Pacific Roots Fresh Green Kava is expensive and may be a tough sell for a newcomer to kava but it works very amazingly due to its strength. It'll have a different taste from dried medium grind but you'll be able to tell it's made from the same plant.
Another option to consider is instant kava. Instant kava is made with fresh root and the resulting grog is dehydrated (after filtering), then the remaining solids are crushed into a fine powder. Simply spoon up the desired amount of powder then mix with water and chug. It's more expensive than medium grind but this is stuff you can easily take to work and mix up with very few tools.
Some vendors I personally recommend: Gourmet Hawaiian Kava (Chris semi-regularly reads the threads here), Bula Kava House, the aforementioned Kalm with Kava, and Kavafied. If you ever make your way to New Zealand or if you have money to spare on shipping, The Kava Society has great products also.