No values are ever given. However, given as how the description mentions that urskans "add steel tips to their already deadly claws," we're not looking for a normal melee weapon--we're looking for a weapon that increases the damage of a natural attack. Granted, there's no damage progression that goes from 1d8 to 1d12, but let's ignore that.
Let's look at spiked gauntlets. They let you deal lethal damage with your unarmed strike, attacks with them count as armed attacks, and opponents cannot use a disarm action to disarm you of spiked gauntlets. More importantly, however, a spiked gauntlet designed for a Medium creature deals 1d4 points of damage, while a Medium creature normally deals 1d3. Small spiked gauntlets deal 1d3 damage, whereas a Small creature's unarmed strikes normally deal 1d2 damage. In other words, a spiked gauntlet appears to increase your unarmed strike damage by one size category.
As such, I'd go with the costs for appropriately-sized spiked gauntlets. Though do note that only a creature with the appropriate claws would be able to benefit from urskan steelclaws.
