Really cheap RX100 (+) LCD protector
And any other camera you may have, too. I was going to order an LCD protector, but hadn't got around to it. Then I went grocery shopping with my wife and saw a 4 pack screen protectors for $3.99. Bought it, why not, only $4!
I also had some generic screenprotectors laying around but I choose to get the Sony PCK-LM12 screenprotector for the RX100 and save myself the DIY actions this time:) Just 13euro incl. shipping. It's a perfect fit of course as it's specifically for the RX100. Yu can't tell the difference with a RX100 without the protector attached.