Since you are new you will probably have to give the keys first in any trade. They are going for about what you paid for them $2-$3 each. Since the market is flooded with them don't expect too much. You might be better off holding on to them til after the sale. Good luck trading.
I see. I might try to sell some on eBay then. I bet someone will buy it for more than 2-3$.
That's a better idea and safer for you, also beware with the friend invitations without a previous post here or private profiles
If you know what you want put in in your title. Otherwise scan other threads offering the same games. If an offer is declined reply to that person and see if you can work out a deal.
Right this minute while the sale is going on at Amazon? They're worth $1.25 each since it's $9.99 / 8 eight games. The idea is to buy keys when they're on sale, then hold them until after the sale and try to get more in value than you paid for them.
Listen to AkinoX great advice never accept random friend invites always check the rep of the person. Make them offer here then you can add them. As for worth they are worth what someone is willing to give for them.
One of these keys for TLR:
Chime
Commandos 3 Destination Berlin
Dangerous Waters
King's Bounty the Legend
Reign: Confict of Nations
Rig n' Roll
Space Rangers
I am new here, and don't really know the 'trade' system here. So I would appreciate if someone told me what game I could get if I trade all these for, or independently.