VBA IF Then语句使用字符串变量

I am working out a problem for my programming class and was wondering if I could get some help. The code below is supposed to get a discount for specific model numbers (AX1 and SD2) at 10% off. All other inputs are to be discounted at 5%. What happens now with the code is just a flat message box with the original entered price.I am working out a problem for my programming c