It would help if you would list the mileage of the car. Next question is whether you or prior owner ever replaced the front struts. If yes, then what brand? You would want to match brands front to back.

Having said that, it is not necessary to replace struts/shocks out of hand.
If you have no handling symptoms and no leaks, leave them alone.

Finally cheapest often ends up resulting in dissatisfaction and more expense over the long haul.

Go with Biltstein.

Steve