Someone may have posted something similar to this, but I did the work so I might as well share. Below is a link to a google spreadsheet I built to help coordinate group buys from HopsDirect. Google docs is a really cool way to coordinate things like this, because once you've invited someone, they can edit in their own amounts, reducing the burden on the organizer.
This spreadsheet is read-only, so google users will need to save a copy before they can drop in names and such. You can grant edit access to people who don't have google (which worked well in our case) but to my knowledge the "owner" of the spreadsheet needs a google account.
The prices on the spreadsheet are up-to-date as of Monday. The shipping column is estimated at $2 per ordered pound. That's what my last order cost to ship from oregon to northern california. If you've done a buy from them before or you're just further away, you may choose to edit that formula.
As a final note, everything on this spreadsheet are whole leaf hops, not pellets.
Anyway, feel free to use it. If you have any comments, suggestions, etc let me know.
Hops Direct Google Spreadsheet
Edit: Another cool thing about the access controls is that you can change user rights after the fact. In this buy, I set all the previous "editor" level permissions back to "view". This allowed me to manually reconcile all partial pounds and give people a chance to do a final review of their order without having things get changed on me. Also, the spreadsheet has an option to email everyone who has access rights to view it, making it really easy to send out notifications and status updates to your group buy participants.