Because only 5,000 copies

of The Soundhouse Tapes were made, they have become the "Holy Grail" for Iron Maiden collectors. The 7" vinyl E.P. was only available through direct mail order, and were quickly sold out. Although several record companies placed orders for 20,000 copies each, the band decided to refuse, feeling that cashing in at that time would have destroyed the magic of The Soundhouse Tapes. Note that Dave Murray did all of the guitar tracks for The Soundhouse Tapes, as the band was experiencing problems finding a second guitarist that could match Dave's abilities.
Due to the extreme rarity of this record, there are quite a few bootleg versions floating around and Maiden collectors should take extreme caution to make sure that they only purchase an original.