Ask at the DIY store for under counter fixings. Best wishes
What type of top or finish is currently on your kitchen island? Could you rephrase your question with some more details so we know exactly what you are asking?
Diy stores have all kinds of tops for islands. That being said, what kind of a top are you looking to put on your island...wood, granite, tile, ceramic, stone...?
here are some inexpensive countertop ideas - https://www.charlestoncrafted.com/inexpensive-countertop-ideas/
Do you want to re-finish your existing top or put a new surface on it or put a totally new top on it?
We can help you with more information.
Juan: maybe some of these ideas will help
Here are some kitchen top ideas https://www.hgtv.com/design/rooms/kitchens/kitchen-island-countertops