Coentrao is obviously the best money can buy but there are other options like Izaguirre from Celtic who might cost less than a fraction of Coentrao (maybe 6-8 million) and Taiwo from Marseille who is a free agent this summer.
There are many schools of thought. If you spend big on one position, make sure that he is a world beater and would sort out your issue once and for all.
But can we afford Coentrao and most importantly if we dont qualify for CL, will he come?