For a more affordable option, stay at Abdul Chalet or Tuna Bay and take a boat taxi when you want to go to the beach at the Perhentian Island Resort.
The Perhentian Island Resort beach is NOT restricted to Perhentian Island Resort guests. If you’re on a tight budget, you can also walk (It takes around 25 minutes from Tuna Bay). However, the walk involves trekking through the jungle, the path is confusing, and there are lots of tree roots etc underfoot that would make it difficult for children. Boat prices are listed and always per person, so two people is always twice the price of one person.
If you’re trying save money, take the boat from Tuna Bay / Abduls Chalet to Coral View Resort and walk the rest of the way to Perhentian Island Resort. This avoids the jungle trekking and is an easy walk with stunning scenery.
Perhentian Island Resort is on Perhentian Besar. If you’re staying on Perhentian Kecil, you can also easily take a boat taxi. Again, if you don’t mind a 5-10 min walk, check the prices for a trip to Coral View Resort vs. to Perhentian Island Resort. You’re likely to be able to save a few ringgits by taking the boat taxi to Coral View Resort.
My only negative comment about the Perhentian Islands is that sea lice stings can be a problem, at least during some months. Personal experience and feedback from other travelers suggests you’re more likely to encounter them in April/May than in June/July.