This varies per park and per holiday home. This information can be found under Facilities on the page of your park and under Amenities on the page of your holiday accommodation. Most parks have free Wi-Fi and the Wi-Fi code is on a kitchen cupboard. If you are staying at the campsite, you can request the Wi-Fi code from reception. Sometimes you do pay for Wi-Fi, the costs differ per park.
For each holiday home mandatory additional costs apply. The additional costs vary per holiday home and can be found in the pop-up displayed with every price. No rights may be derived from these prices.