Worse is that Amazon sold this bundle for $7.49 back in November 2012. I haven't seen the sales price matched since. Even camelcamelcamel doesn't have records going back that far for the pack in question.
Went back and checked. Looks like the pack had the same discount in 2013 but has seen smaller discounts since.
If you live in the U.S. and you don't feel comfortable buying from https://buy.guildwars2.com (this is directly from them and you can ask for a refund if health problems arise), give Amazon a try.
This product should allow you to get a pre-purchase code, giving you permission to play in any more stress tests before release, and let you play Aug 25-27th before the game comes out and ArenaNet asks everyone for a full game key. You can cancel the order after they give you the code, and not have to pay $60, but you should give it a try before you just go and cancel! I've never seen a game that justifies spending $60 more than GW2.
I bought the DA Complete pack from Amazon back in 2012 ($7 with the $5 coupons), but didn't actually use it until recently. (I started playing DA:O a week or two ago.)
In any event, I already had DA:O in my Origin account -- not sure if I got it for free or I bought it previously and forgot about it. (I had save games for it from 2009 on my computer, so I guess I bought it back then and got distracted and never finished it and only vaguely remember it now.)
Either way, I tried to do what you suggested -- use the key for the bonus content and save the key for the base game. When I did this, Origin did have options to download all the included DLC (they extras key provided them and that seemed to work) and I did so, but the game never actually saw or would use any of that DLC.
Also, DA:Awakening was missing.
But when I redeemed the DA:O Ultimate Edition key, the DLC all started working and DA:A appeared as well.
... so, I think you may not get a second copy after all, but instead just a partial copy. You could give away the DA:Ultimate Edition key, but they'd get Awakenings and you would not and I'm not sure but it may be that nobody would get the DLC ... or maybe that was just a fluke on my part.
why are you buying from blizzard? if you spend a few minutes looking around you will find better deals. http://www.amazon.co.uk/Starcraft-II-Heart-Swarm-Mac/dp/B00A6OP29E/ref=sr_1_1?s=videogames&ie=UTF8&qid=1421611664&sr=1-1&keywords=heart+of+swarm
Buy both:It is on sale for Amazon. Civ IV the complete edition and Base Civ V.
You could wait until the end of the week to see if there is a better deal on Steam, or bight now.
Also, the Civ V DLC is discounted right now on steam.