(PF1e) How to compute cost of combined magic items?

[Endarire]

Greetings, all!

I’m soon to play in a game where we use PF1e’s craft rules. I have Craft Wondrous Item as a definite feat pick. However, for personal reasons I intended to combine items into a single slot like a Headband of INT and a Hat of Disguise.

Thus, what is the final cost of these items?

For example, if I combine a Headband of INT IV and a Hat of Disguise, what is the total craft price?

(Please keep to topic. This is simply a Q&A thread, not an optimization one.)

[GeoffWatson]

Cost of one item, plus double the cost of the second one. If the DM allows.

[icefractal]

It's the cost of the most expensive, plus 1.5x the cost of the others. See "Multiple different abilities" in the Magic Item Creation (https://www.d20pfsrd.com/magic-items/magic-item-creation/) rules.

Note that these are subject to GM discretion, although IME that particular one (combining items) is pretty harmless and when GMing I'd approve it for pretty much anything.

The one that you should take with many grains of salt is the "Command Word / Use Activated / Continuous" formula for spell-based items. It's a starting point, but it's overpriced for many spells and severely underpriced for a few of them.