I run a rather lighthearted campaign that contains a number of re-flavored elements, including items. For the most part since these are based on published items their actual value for sake of crafting and selling is easy to discern, but items with no direct counterpart are a bit harder to calculate. Is there in existence a guide, official or unofficial to assigning value to homebrew items (which by that extension would help with craft time and the such)?
As a couple of examples of what I refer to- how would I actually derive the value of an artificer's +5 Use Magic Device item? Say I had a fighter type that wanted to get someone to craft an item that could produce a flaming scimitar effect at will (as a replacement weapon). Even something as simple as a magical spice that could reflavor anything to taste like a specific food (like a really weakened prestidigitation effect) would theoretically have greater impact that it first appears (especially in the hands of a poisoner).
I know that as the dm and it really is up to my discretion, but it would be nice to have some form of guideline to go by.