How to create an asset with a reduced value compared to my regular currency (dollars)

[Mariano, Adrian V.]

I bought a $500 gift card for $430 this week.  I would like to add this to gnucash as some kind of asset so that as I spend it, the correctly scaled amount gets transferred to the expense account I use.  In other words, if I spend $100 from this account it's really only $86.

I tried to do this by creating a security fund and then using the price editor to set the price to 0.86.  But when I insert a transaction from the new account to an expense account, it doesn't apply the 0.86 factor.   What is the right way to do what I want to do?