is it like a just bulb or a ballest and bulb? or do you already have the ballest?

I would also be scepticle of second hand bulbs. can you get any info in it. Like how long it has been used for and stuff like that.

On a side note. It might be worth picking it up just to have as spair. That way if you main bulb braks you don't have to be panicking about getting a new one.