I am offering a guided service for individuals. The initial package they purchase includes lodging. However, should they want to bring their wife or kids, there is an additional lodging fee. I would like to add a variant permitting them to select the number of variants at an additional $75 fee per evening. How would I go about adding this variant? Attached is a link to my website.
You would swap your existing package to one where the first variant is your base price and the option is then either additional nights or additional people (not sure from your post which one you need).
Just set the first variant as 0 for your variant value and adjust pricing for all other variants.
Let me know if you need more help.