Regardless of the time of day you decide to fly, the ticket price will remain around the same. Book flights from Pretoria to Johannesburg as you normally would.
For a flight from Pretoria to Johannesburg, you will be flying from Wonderboom Apt.. Pretoria Wonderboom Apt. (PRY) is just 10,7 km from the centre of the city. Wonderboom Apt. is the only Pretoria airport and it handles 0 outbound flights to Johannesburg per day. 0 airlines have flights to Johannesburg from Pretoria Wonderboom Apt. on a regular basis.