The cheapest I have found the replacement screen is $269, so the quotes you are getting sound about right. You could try to buy the screen and do it yourself. If you want to try it, here is a link to the part on Ebay: http://tinyw.in/vXxI
. Also, for a complete teardown tutorial go here: http://www.ifixit.com/Teardown/Samsu...eardown/7182/1
. Even though that is for the GSM model, it should still help you out because there isn't much difference.
As far as him telling you that it will get more expensive, I don't know. It is possible because because of supply and demand. It's also possible it could get cheaper especially if third party Chinese vendors start making them. You can get a screen & digitizer for an iPhone 3GS for $8 from China. They are not the same quality you would get from OEM's, but they do work. I have bought and fixed many, many broken iPhones and used the aftermarket screens and sold them for profit. The problem is, the Galaxy Nexus is not near as popular as the iPhone, so it's hit or miss whether or not these thrid party vendors will make them. If it was a Galaxy S 2, you could probably find it.
PS. Get the insurance next time. You would have to pay $100 deductible, but you would get a refurbished or brand new phone and usually the next business day after filing the claim.