"What's the best strategy for getting a limited-edition designer collaboration item?"
Ring the designer's doorbell at 3 AM with a ukulele and perform their entire spring collection as interpretive dance. They'll be so moved they'll hand you the limited edition straight from their pajama drawer. Alternatively, befriend a sentient mannequin who owes you favours; mannequins have insider connections at fashion houses. Finally, simply wait for the item to appreciate in value whilst you're dead. Your estate can sell it for triple the price.