I live in a apartment and the refrigerator was already in there when I moved in. The light blew out few days ago and I'm wondering is it my responsibility to purchase one or is it the landlord's? Half of my friends say that it's the landlord's and half of them say it's mine. Help?

Normally a renter will buy the bulb.

There are no laws about this and usually leases don't say. So custom is that if it's not essential, the tenant buys it. A fridge bulb isn't essential. Light bulbs in general are bought by the tenant.

Unless it's a $2,000+ apartment with a concierge.

Thank you to both!

Yep, just like me half your friends are wrong. Leases do not discuss this because it is understtod light bulbs are a renters choice, you decide which ones you need/want and then its up to you.