The effect on the Volsung helm is supposed to make prices 20% better. It does the exact opposite, increasing vendor prices when worn.

It also has zero effect on horse pricing, maybe that's intentional though.

Nothing and everything has a price. There is no currency, you are the author of history, if you wish the bend the reality of others by means of some "magic" artifact you might aswell bend the reality by realizing the fact that reality does not excist and that everything is dreamed. So you dream yourself untold fortunes and acquire whatever you wish, does this make you happier?