Hi,
When I had renter's insurance, I just went through the same insurance agency I have for my car insurance (you'll get a discount because you already have car insurance with them) which was Allstate. From what I remember, the policy was based on a certain set amount of money based from square footage of my place (they may have asked me basic questions of items I owned, but I can't remember). I didn't have to show any receipts, pictures, video, etc. My place was in downtown San Diego, 950 square feet and I believe I paid around $20-$25/month - perhaps even less. I remember it being surprisingly inexpensive for the number of people who don't buy it.
The insurance company will spell it all out for you and it is definitely something you should invest in.
Best,
S.