Price of this domain such as this is more expensive than the TLD, because it is more representative. However, on its official website at Register.science registers, starting in a few days ago this domain providers provide free promo .SCIENCE registers domains for 1 account and 1 year of purchase.
There is no requirement to get this promo, only list and enter the promotion code. Below is how to register .SCIENCE domain for free.
Promotion Code: ForScience