I have a question regarding pricing products.

Let’s say I have a product, price=x        
But now it has increased by 5%, so p=x+(x*5%)

How to deal with this change in price, since we have got it with x and now it’s x + 5% or any amount.        

What should I record in excel for that product price?

x OR x+(x*5%) ?        
IF x why not x+(x*5%) ?     
IF x+(x*5%) why not x ?