Dear Syag
What you did was very commendable. Halachically, it was “lifnim meshuras hadin”. There certainly was no gezeilah or gneivah on anyone’s part.
One could have made a reverse argument. Assuming you knew you had these items that you would gladly give your friend at no cost, why would you allow a situation in which your friend had to incur an unnecessary expense? Why is the profit (minimal) of the store inherently preferable to the expense (maximal) of your friend?
Don’t sweat it. you did a noble act and you need not worry about it.