If you've reached the standard number of twenty questions in the online hosting of your questionnaire and you need to add some more, simply:
Note: If you're purchasing a full-service study (all five modules), it's more cost-effective to add the necessary number of Full additional questions, rather than the number of additional questions for each of Design, Hosting and Primary Analysis.
Add an additional question to your online questionnaire hosting. Set the desired quantity before adding the product to the cart.