Hello,
We see 2 solutions for have what you requested :
1. You can use the option plugin, if you have elements to added to your main products, such as accessories, equipment or spare parts.
See this
documentation
to learn more about this.
2. If you use the Characteristics to generate variant from your main product (learn more about Characteristic/variants,
here
)
When you will have generated variants, it will be possible to enter for each variants a different price.
Later, when user will select different variant, price will be automatically change, before the add to cart and the checkout process.
Hope this will help you to achieved what you need.
Regards