[Discounts] Use relative values % for small discounts

The hypothesis is that from a psychological point of view, in the case of low-value products, a 35% discount (from $10 to $6.5) is much more advantageous than stating that the visitor is saving only $3.5, which would seem to be far too little to incentivize the visitor.

Thus, in this case, the relative discount of 35% will be perceived as greater than the absolute discount of $3.5

See https://thedecisionlab.com/biases/hyperbolic-discounting