Hi,
In your case I think that the best way will be to combine variants and custom fields.
Thanks to the variants, you can define different prices for sell or rent for each products and via the custom fields you can restrict the display of some of them to others.
The only thing is, you will have two times the same dropdown, one for the variant selection and so price variation, and another one to display/hide the associated custom fields. To have only one dropdown you can potentially hide the custom field one (rent / sell) with some css and add some javasript to change its value when changing the variant value.
It require some Javascript knowledges.