at a scrapyard driveshafts are usually £20 each if you remove them yourself.
you dont have upper arms, your suspension is only single wishbone.
or do you mean the strut (spring and damper as a whole ready to fit)? i have never bought one from a scrapyard so tbh i dont know, but it cant be much if you remove it yourself. i would always replace both sides, taking both from the same donor car.