I could've sworn I saw a version of Sims 3 at a regular price of $19.99, but looking through the storefront once again I guess not? Using the Slick Deals link in the op brings Sims 3 to $12, though. That's not bad. I think Sims 3 + Pets is $20. If you really want Sims 3, I'd go with that and then use the coupon on some Stuff Packs or the premium towns.
Sims 2 Double Deluxe is good, too. No reason to not get it if you want it - unless you want something else more.
Yeah I couldn't get any of the Sims 3 games working so I went for that Sims 2 Double Deluxe. Thanks for the help.