You will be able to file one return on Turbo Tax Online whereas the Desktop version allows you to prepare and print unlimited federal tax returns, and e-file up to five at no charge (additional fee per state e-file with TurboTax CD/Download). CD/Download is a better overall value for customers preparing tax returns for multiple people.
https://turbotax.intuit.com/best-tax-software/common-questions.jsp
You can also compare pricing using this link:
https://turbotax.intuit.com/personal-taxes/compare/online/
