Sometimes a tank lid breaks. You drop it while fixing the flush lever, the kids knock it off while playing around or any number of things can happen to break the darn thing. You would think replacing it would be as easy as pie, but it is not. Getting one to match can be frustrating. The toilet makers change styles more often than the fashion industry and each time the lid is a little different. I guess they hope you buy a whole new toilet. This can be expensive and if you are not experienced, hard to do.
At Gersons we have over 1,000 toilet tank lids. Hopefully we can match it up to your toilet. Bring in the old lid, or parts that you still have, and we will see what we can do. OR take a piece of cardboard and make an outline of the top of the tank. That sometimes allows us to fit it better. Numbers do not hurt, but not all of the lids have numbers.
We do have better luck with older tank lids than brand new ones. Newer toilets just are not taken out as much, thus fewer lids. We charge $25 for a tank lid. If we do not have the proper lid try these guys - PlumbingSupply.com. They have several thousand lids and a lot of good toilet information.