There are few things you need to know that affect the price before ordering:
1. Which height do you need? If it will sit on a raised platform you need the short ("standard") version...if not, you need the more expensive tall version.
2. Slant or straight back? If it will sit against a vertical bulkhead, you need the straight back...against the hull, which slants toward the keel,, you need the angled back.
3. It's designed to use pressurized fresh water...if you want to use sea water, you'll need a remote intake pump.
4. There are three flush options: basic push button (simultaneous water in, bowl contents out), slightly more expensive 3 option "momentary flush" (add water to the bowl ahead of use, "dry" flush, and same simultaneous flush as push button) and pricy "Smart Flush" panel that adds a 4th option, "full flush," that uses quite a bit of flush water and has a circuit board (failing circuit boards created enough problems in the refrigerator in my kitchen at home to last me a lifetime! I always recommend the "momentary flush."
Boatersland
Boatersland Marine Elegance is my favorite retailer. You may be able to find the ME for a few dollars less, but the boxes in their listing are actually menus that show all the options, and their shipping is reasonable.
--Peggie