What would you do in Kauai on a limited budget?

If you have a rental car, you should drive around and see the sights. You can get a free travel guide at the link below.

You can go to the second link below and find all kinds of activities to do. Choose those that are the least expensive so you can do more.

I would visit the different beaches. They are really beautiful. You do not have to eat out every night if you live at a place that has a full kitchen. My wife and I stayed at a resort and cooked a lot of our meals as there was a Safeway grocery store across the street. Lots of other people did the same thing.

JoJo's shaved ice is really good. So many flavors to choose from. I would also visit Kalalau Lookout as you can get a great view of the Napali Coast. If you go to a timeshare, they will give you a good deal on either a helicopter tour or a boat ride to the Napali Coast.

I'd go surfing (wouldn't cost anything if you already owned a board)

Then I'd go on a helicopter tour.

Then I would go to a rural coastal town, because I heard most of the urban areas of Hawaii are ghetto as hell.

Hiking and snorkeling are always fun. The botanical gardens are also nice.

ocean, only shave ice