Hey Acopispo, thanks for your interest.
I guess the short answer is: it depends on what you want from your game.
FWIW--there are no XP values for magic items in the original, 1974 booklets. However, as time went by other players clearly came up with similar questions because in 1975, EGG published the following response to that question in The Strategic Review #1.2:
Low value should be placed upon magical items as far as experience is concerned, as such items will be highly useful in gaining stilI more treasure. Thus, in the Greyhawk campaign a magic arrow (+1) is worth a maximum of 100 points experience, a +1 magic sword with no special abilities is valued at a maximum of 1,000 points, a scroll of spells at either 500 or at 100 points per level per spell ( so a 6th level spell is worth a maximum of 600 experience points), a potion is worth between 250 and 500 points, and even a genie ring is worth no more than about 5,000 points maximum.
What seems curious to me is that while EGG begins by justifying why magic items shouldn't be worth much XP, he then immediately goes on to mete out XP values of up to 5,000 for a genie ring!
In my own games I've tried both approaches. I've found it's simpler to give zero XP for magic-items; it makes a whole bunch of work and potential problems vanish (i.e., figuring out what everything should be worth, and then what happens when a PC gets XP for an item then gives it away? Or dies so that another PC can then recover the same item?).
Not sure if this answers your question entirely, but I hope it helps some
the Elf Medium (MV 12", AC 9, HD 1, hp 1/1, AL N) great cloak, lantern
; spells: color spray; scrolls: sleep, sleep, charm person
Hirelings: Georges; torch