Anyone knows a kind of ready-made countertop which can be placed over existing old counter?

Answer 1

If the existing counter has a built-in backsplash, you will probably have to remove it. There are laminate materials you can apply over existing tops. This would be the easiest and least costly.

Answer 2

You can get counter tops made in natural stone, such as granite or marble;or in synthetic stone; or in timber; or in plasic laminate finish. It's usually best to remove the old tops before you fit the new ones, otherwise the finished top may be too high, or it may not be secure.