There is no cost associated with viewing or crossing the Royal Lelystad Bridge. It is a public infrastructure element.
Access to and passage over the Royal Lelystad Bridge, as with most public road and rail infrastructure in the Netherlands, is free of charge. There are no tolls, admission fees, or parking charges specifically for the bridge itself.
Any costs incurred would be related to transportation to and from the bridge (e.g., fuel, public transport fares) if one were to make a special trip to observe it. There are no commercial services or facilities at the bridge that would incur costs.