Does a c-section leave a big scar and a lot of scara tissue?

Depends. It really depends to the person and the conditions under which the surgery was performed. If there was an infection at the time of the c-section or if there was more than normal bleeding then there may be more scar tissue later.
There is a scar. A c-section will leave a scar. It is not as bad as some types of surgery but it's not as good as bandaid surgery to remove the gallbladder. Usually the scar is placed low in your bikini line so it will be hard to see. Ask the obstetrical nurses which doctor makes the best scar.