Animation cels can be pricey, however this one appears here because it's very rare and unique. First, as you can see it's much larger than an ordinary cell, as it is a panoramic cell. It also has 2 layers, which is rather rare as well, along with containing most of the characters all at once. Certainly, a cell like this is extremely exclusive but...
to add even more, it's actually also a deleted scene! It is from the pilot episode of the SatAM series, with original matching background. You can see that it took place in the 'pre Robotnik' time period for the show--the white arcitecture, trees etc. You can also see the odder looking Boomer/Rotor walrus and the Sally here is pink with black hair. This also had 3 sketches and its certificate of authenticity. Certainly it is a jewel in any cell collection!