the break in period is about 100 hours, thats about two weeks at 8 hours a day, so thats not a big deal, are you buying this sight unseen?, do you actually know this person or just from online? There are a lot of things I prefer to buy used, bulbs arent one of them, if it is really 3 months old, and has been used correctly, it should have roughly 66% of its usable life left. thats based on 9 months of useable life, roughly 2/3's left. What bulb is it? I use 250 watt mogul bulbs, and the preices range from 55-85 + shipping, I recently bought a xm 10k for right at 75 bucks shipped, in all reality the bulbs arent terribly expensive, I dunno, I probably wouldnt do it, and if I did I would pay 25-30 bucks max, if it was only a week or two old I'd say 85 to 90% of the cost