This TurboTax FAQ lists some possible reasons why TurboTax is telling you that you that your wife self-employed: Why is TurboTax telling me I'm self-employed?
If she has income that is considered "self-employment", then she will need to use TurboTax Self-Employed Online. Please see these TurboTax FAQs for more information:
Why did I have to upgrade my TurboTax Online edition?
Who can file for free using TurboTax?
If you prepare your return together with your spouse, then you will both will be using the same version of the program, and you will both be charged the same price. You can only prepare your returns in different products if you prepare your returns separately.