I have a younger brother that is getting into archery and shoots a low poundage bow(I think its like 35-40# if I remember right) He needs arrows and doesnt have a archery shop anywhere near his house so he has to go to walmart. Well he called me and I told him the right spine he needed(.600). But he's not sure how to find the spine on the arrow. So all I need to know is if Walmart sells youth arrows that will fit his needs?

yes but they might not be the right lenght ......... you can buy arrows online and if you know what is arrow lenght is the online store will cut and put inserts in but if you don't you need to find the nearest pro shop so the proper lenght can be determined....