What are some inexpensive science experiments I can do at home to make a 6 years old child enjoy science?

Thanks for the invite I agree with the answer, Ms. Ghada

Thank you for the question,

You can find hundreds online. I give you here few links:

https://sciencebob.com/category/experiments/page/2/

http://kidiscience.cafe-sciences.org/experiences-a-la-maison/

http://www.petitesexperiences.com/petites-experiences-a-faire-a-la-maison/

Thank you for this question

To make your child has a scientific skill:

Scientific Games

Magnetic letters

Educational songs

Health Food

Thanks for the invite .............. Support answer Dr. Ghada

I agree expects answers, thanks for the invitation. 

Floating and sinking using a glass box like that of fish (or the bathtub), a piece of metal like a coin and a rubber duck

You can use it to teach science, and first conditional. 

Something with magnets, Balloon, soap, soap bubbles, thread, strings

I agree with all the previous answers

I would agree with the answers that really covered your question and gave helpful examples about such topic !

Thank You

A Compass or a gyro (powerball rather then toy) could be a good start.

A prince Rupert's drop is great too, provided you have access to right materials and right protection.

At that age, mixing chemicals that change colors or precipitate/dissolve is also a good start, but the hardest part is not to explain it all at once to the child, but let the mystery of things yet undiscovered remain.