Hi there, Maria! Welcome to the Disney Parks Moms Panel! We appreciate you taking the time to reach out and ask your wonderful Walt Disney World Resort question!
It looks as though I'm also having a bit of difficulty finding the prices for a one-day park ticket on the
Walt Disney World Resort Europe website, as well! However, the price of a
one-day park ticket on the Walt Disney World Resort USA website is $109 which is 97.18 Euros. This is, of course, the current price and all prices are subject to change. Hopefully, this will give you a better idea for your budget if you choose to wait and purchase your park tickets when you arrive in the USA!
Additionally, Guests are definitively welcome to use multi-day park tickets on non-consecutive days! Tickets must be used
within 14 days after the initial date of entrance. So, you and your family are welcome to take days off in-between visiting the parks. In fact, I often recommend Guests take "relaxation days" in which they have scheduled downtime to take in the amenities of their
Disney Resort hotels at their leisure. This can be a great way to rest before another adventurous day of exploring the parks!
I hope this information will assist you in planning for your 2020 trip to Walt Disney World Resort! Please let us know if we can answer any other questions for you!
~Wyatt