[Jack Simth]

Detect magic doesn't have any associated costs (other than the spell slot), but at best yields strength of the item and spell school (spell school if you roll well). Neither Jake nor Jacob (the Druid I'm building) have access to Identify to really tell what the item is and does (not that it would make much difference - the material component costs 100 GP, and as it's a 0-level spell, the cost to hire a wizard for it is only 10 GP - which means 110 (10 for spellcaster, 100 for material component) to hire or 100 to cast). However, in order to sell off the anklet, it first needs to be Identified - and I don't have that info. Jake/Jacob can pay the GP - but the GM (you) is the only one who can answer the questions "what's it do" and "how much is it worth". In inventory, it's listed as a "Mystery Anklet (magic)". The case is essentially the same with the book, only it first needs a Detect Magic to see if it needs Identify.