Where are the rules for crafting Skill Enchantment bonus items?

Question

I have been looking at guides for dramatically boosting a character's potential with a single skill. In addition to toolkits, I have found mention of Competence bonuses and Enchantment bonuses (or “Enhancement” maybe?), but I cannot find the actual costs of making the skill enchantment bonus items. I have seen many references to these bonuses but am failing to find the information needed to craft them.

Answer 1

The Table

I believe the table you're looking for is Table 7-33 Estimating Magic Item Gold Piece Values on PHB 285. The two rows you're interested in are

\begin{array}{l|l|l} \textbf{Effect} & \textbf{Base Price} & \textbf{Example} \\ \hline \text{Ability bonus (Enhancement)} & \text{Bonus squared} \times 1000\text{ gp} & \textit{Gloves of Dexterity +2}\\ \text{Skill bonus (competence)} & \text{Bonus squared} \times 100\text{ gp} & \textit{Cloak of elvenkind} \\ \end{array}

I don't believe there is any magic item (in the core rule books, anyway) that directly provides an Enhancement or Enchantment bonus to a skill.

However, all skills are based on an attribute (strength, dexterity, constitution, intelligence, wisdom, or charisma). An Enhancement bonus to that stat (say, a +2 Cloak of Charisma) will provide a boost to skills based on that attribute (for Charisma, say, Diplomacy) as if your attribute were naturally that much higher.

Crafting

If you're interested in crafting these items yourself, check out the PHB's Feats section for feats such as Forge Ring (PHB 94) or Craft Wondrous Item (PHB 92). The cost to create an item is 1/1000 item price in days, 1/25 item price in XP, and 1/2 item price in GP for materials.

There are also special requirements for some items; namely, for the competence bonus items, the creator must have ranks in the skill equal to the bonus the item will grant.

Answer 2

The guidelines for creating magic items are just that, guidelines, which in this case means they explicitly state that every potential item you might make has to be specifically approved by the DM. You can’t just assume you can make whatever you want, or at the price indicated, because the guidelines do not provide a complete, fool-proof system, only suggestions and starting points.

That said, Table: Estimating Magic Item Gold Piece Values does include this:

Effect	Base Price	Example
Skill bonus (competence)	Bonus squared × 100 gp	Cloak of elvenkind

This implies that you can keep increasing that bonus, and as long as you can afford b² × 100 gp, you can have it. As noted above, that’s not really the case.

Also note that Epic Levels Handbook defines any item worth 200,000 gp or more as an epic item, and also any item that grants an enhancement bonus to a skill of greater than +30. (Despite this, Estimating Magic Item Gold Piece Values does not include enhancement bonuses to skills.) Fitting within the 200,000 gp cap means you cannot have a competence bonus larger than +44.

Realistically, most DMs are going to want to cap it far, far sooner than that, just so you can’t trivially buy all the skills in the game. In the core game, there are a select few high-competence-bonus items (robe of blending grants +10 to Hide while you wear it; salve of slipperiness offers +20 to Escape Artist for up to 8 hours), but most are limited to +5.