That depends on which Cessna. Many of the earlier Cessnas were made to run on regular auto gasoline, however now most need avgas or jet fuel.
100 LL Avgas.
Avgas 100LL
A Cessna is a type of airplane.
how much fuel does a 406 Cessna take
There is not, and never has been a Cessna called 'Mustang'
You nust have a number wrong, there is no record of a Cessna 142
That there is no fuel in it!
20.3 gallons
There are many different kinds of Cessna so your question is un-answerable.
Avgas 100LL
It depends on which Cessna you have, whether you have added auxiliary fuel tanks to it, and how much cargo and pax you are carrying.
The Cessna 182 will use 11-12.5 gallons per hour.