What are you expecting, opening a galactic cheese empire?

Colonies and cards from hand are the only offereable items.

I know that the Zombie can free ships as part of a deal, so I know that it is not just cards or colonies. Anyone else have something they use to make deals?

So far nothing else.  Although you can make promises of future actions (provided they are legal), these promises are not enforcible and do not themelves constitue a deal; that is any such promises must come in addition to an exchange of colonies and/or cards (or zombified ships).  

A good house rule might be to allow the return of captured ships (by Fungus or Fungus wild) as legit terms of a deal.

From the official FAQ:

Q: Are the terms of a deal EXPLICITLY RESTRICTED to one or more of the following categories:
* granting a single colony on a planet you already occupy
* giving cards from your hand
*specialized use of your power where indicated (such as Zombie's regeneration)

A: No, but either colonies or cards must change hands. Anything else you choose to negotiate with is up to you. Any other terms you set are not enforced (i.e. if you agree not to ally against each other, either of you may break that portion of the deal.)

Also, remember that you are allowed to be more specific when going for cards in a deal. You could ask for their highest attack cards or if you know they have a particular card, like your race's flare or a morph, you can try to get it.

xagyg said:

Where can I find the official FAQ? Is it online or was it included with the game/expansions?

Look in the Support section of the FFG Cosmic website here.

Toomai said:

I'd take that deal...

You, can offer pretty much anything even money. $5 for a colony. However I believe the rules state there must be an exchange of a minimum of one card or colony. Other than that you can put anything on the table. However any future considerations are not enforceable. For example if a player offers future support in your next encounter there is nothing that stops him from forming an alliance with the opposing player stabbing you in the back. The consequence is that players will be less likely to trust him in future deals if they go back on their word.

If someone asked for, say, your three highest attack cards, how binding is that? The inclination to respond with three negotiate cards out of spite is entirely natural, but can you legally bald-facedly lie like this?

Certainly would make for some humourous negotiations