To get absolutely everything, you're looking at just one option: US$79.99 for the Digital Deluxe Edition at Origin, as Plumbob Park is exclusive to Origin. I suppose you could also do the Limited Edition on Origin and upgrade to the DDE later if you wanted. Either way if you want Plumbob Park pre-order perk you need to buy one of the three flavors on Origin before March 4.
Plumbob Park aside, Amazon has the standard Limited Edition for US$44.99 for download if you use the promo code CAGROCKS (US$59.99 minus 25% discount). It previously included $5 of credit with Amazon, but that's not listed on the page any longer, so I doubt that you'd still get it. As far as I'm aware this is the cheapest you can get the game as far as least amount of money out of pocket.
Amazon also offers the physical edition for US$59.99 with a US$20 credit. As far as I know this is the cheapest I've seen it, since that effectively makes it US$39.99 - they very well may even sell the DDE upgrade after launch (since they sell other Origin codes/DLC as well) which would give you the DDE content, minus Plumbob Park, for US$59.99. Even if they don't sell the DDE upgrade, $20 at Amazon is practically as good as cash IMO.
I think in the end it just depends if you want absolutely everything or almost everything.
SimCity - Limited Edition (Amazon.com)
Nope, it's still on sale. BUT they do include this notice:
Important Note on "SimCity"
Many customers are having issues connecting to the "SimCity" servers. EA is actively working to resolve these issues, but at this time we do not know when the issue will be fixed. Please visit https://help.ea.com/en/simcity/simcity for more information.
EDIT: I do notice that the download edition is not available for sale, only the DVD copy.
http://www.amazon.com/SimCity-Limited-Edition-Pc/dp/B007FTE2VW/ref=cm_cd_f_pb_i
Sale's still going. I'll take Amazon credit over a useless Origin voucher any day of the week.
To be clear:
Go to SimCity Limited Edition on Amazon http://www.amazon.com/gp/product/B007FTE2VW/
Buy it, it does not charge your card anything until after it ships (in March)
Cancel the order (you'll receive a promotional email with the beta key)
I was a little worried as I had no money on my account, and didn't want to get overdraft fees. I tried it, and yep no charge to the account :)
Also, you can do it multiple times to get different beta keys (I'm bad :()
Went to check it out. Looks like only the digital version is unavailable. However, this could be due to the fact that Amazon has simply run out of digital keys. The physical copy of the game is still for sale.
Usually, when Amazon "withdraws" a product from sale, they will say something along the lines of "We have received numerous complaints about this item and are currently investigating these claims." etc etc. I don't think this is the same type of situation.
[EDIT] Although, on further review I did notice the following statement by Amazon:
"Important Note on "SimCity" Many customers are having issues connecting to the "SimCity" servers. EA is actively working to resolve these issues, but at this time we do not know when the issue will be fixed. Please visit https://help.ea.com/en/simcity/simcity for more information. "
Good on them to inform the customer.
Amazon Right Now - $59.99
$20 Amazon Credit; Access to Beta; Limited Edition
Edit: Physical Copy only ($5 Amazon Credit with Online Download)
At first I am (and still) sick of the whole Anti-EA jerk. I too rolled my eyes at the whole server nonsense because launch day with servers are always like this. Reddit blew up when Diablo3 did it and it I knew it would do it again without a doubt because it was EA. Yet honestly I understand why its such a hot topic now.
The game is STILL unplayable and to the people who can play it EA removed the features (like speeding up time and leaderboards) it so bad I read a IGN article yesterday (the same website that called ME3 fans spoiled for wanting a better ending) to NOT BUY SIM CITY IN ITS CURRENT STATE and amazon has a warning on it
Is the Reddit anti-EA jerk annoying as fuck? Yes it is. Yet I understand it this time. EA dropped the ball hard on this one. Even D3 balanced itself out in a day or two without Blizzard removing bits of the game. The whole DRM thing was stupid to tack on to a simcity game.
Amazon has it for $35 for PC, $40 for Mac. There's also some people selling it for as low as $20 on Amazon.