Not too much. The world is full of distortion pedals.
Agreed. And so many people make those hundreds of distortion pedals because it's so easy to cause a circuit to distort.
That said, there is still some GASsy market you may be able to tap into, because the existing pedals don't satisfy everyone--
or they are too expensive for most people. IOW the perfect bass distortion pedal for each of us probably
exists already, but for some people it's going to be a $350 to $650 BJFE, Dirty Boy, or Schumann, etc., and for other people their ideal maybe isn't at such an outrageous price, but there are only so many dirt pedals the average bassist will be willing to buy on a gamble to find out which one will suit them... especially since the Sansamps and MXR's of the world are pretty decent and readily available to try out.
Here are my two thoughts on how you may succeed:
Bassists who gig regularly in a rock band want to cut through the mix. Their complaint is of pedals that rob the mids, and that muddy their tone or articulation. For them, you want to be able to advertise that your pedal will not have those failings.
Bassists who mainly play at home or in smaller band settings often want their sound to be not too harsh or buzzy--they may prefer a pedal that allows some rolloff of the highs, or where the highs are not too ice-pick-y. For them you want to be able to advertise that your pedal has plenty of grit and growl, without sounding fake or annoying.
As far as the price, I don't understand why you are asking us this. Just go to any pedal retail site and look at the prices of the pedals they already have. That is the range different people may be willing to pay.