You can still use the Free Edition if you qualify. Or it will ask you to upgrade when you enter something that needs a higher version.
Here's some general info on getting married. Did you both use Turbo Tax last year?
You can not transfer from or combine 2 returns or accounts. Just pick the return for the spouse that has the most complicated return to enter or has any depreciation or business or more investments. Or use the account for whoever you want to be listed first going forward (by the way you can not change the order of the names). Then add the other spouse's name, ssn and info to it.
You should usually file a Joint return which is only 1 return combined for the both of you. Make sure to stick with this one account for the future. Just ignore the other spouse's account.
Getting Married FAQ
And info on Getting Married…..
http://turbotax.intuit.com/tax-tools/tax-tips/Family/Getting-Married/INF12006.html
Is it better to file Joint or Separately?
You can still use Basic for filing jointly. If at any time you enter information into your return & you need a higher version, the program would tell you to upgrade. You would only pay the upgrade price.