What does a club of size Large or bigger cost?

Question

I'm working on a Master of Many Forms. Given that not all forms you can turn into creatures with high strength but not too spectacular natural attacks (Giants and such), I want to arm him with a weapon. My eye fell on using clubs, carried around in a Vestment of Many Styles on a Wildling Clasp with the effect of a Handy Haversack enchanted into it.

Now, I could use an enchantment to scale a club to my size (large, huge and so on), but this prevents Shillelagh being cast on it. So the solution sounded simple to me: carry bigger clubs.

The damage and weight are not difficult to calculate for bigger weapons, but what about cost? A Medium club has no cost, so how about bigger ones? I don't think the material used for Shillelagh (oak wood) has any specific cost to it, so I believe that's not an issue here.

Answer 1

The basic rule for weapons, under the equipment section, is:

[The weapon's] cost is the same for a Small or Medium version of the weapon. A Large version costs twice the listed price.

So most Large versions cost twice as much. But since a club is free, a club for large creatures is also free. Huzzah!

What about masterwork weapons? Interestingly, the price increase does not apply to the masterwork component (DMG p.223):

Weapons for Unusually Sized Creatures: The cost of weapons for creatures who are neither Small nor Medium varies. The cost of the masterwork quality and any magical enhancement remains the same.

So a masterwork club sized for large creatures will cost the same as its tiniest cousin, 300gp.

Answer 2

Ripped down trees are free.

The SRD notes that:

This cost is the same for a Small or Medium version of the weapon. A Large version costs twice the listed price.

Therefore, a club, having no cost, has no cost multiplied N times, to be no cost. With that said, a masterwork tree or a club made out of exotic materials may start getting quite pricey.