A satellite dish is typically easier to install and the cost of the materials are approximately the same. A standard satellite dish installation, which would be a mini-dish installed in a south-facing wall with a cable up to 15m meters would cost less than an aerial installation that would need to be installed on the roof and may take twice as long. But the important factor here is that with the combined cost of a satellite receiver which will be required to decode the satellite signals this would usually make the satellite TV service more expensive to install.
If you live in a large property then installing a TV aerial may just be out of the question owing to gaining access as high as you need to be. In situations like this, a satellite dish would usually be the most economical option. This is because satellite dishes receive their TV signals from satellites up in space they can actually work on the ground providing that the satellite dish has a clear view of the satellites and there are no obstructions blocking the signal. Because TV aerials receive their transmissions from land-based transmitters more often than not they need to be installed high up on the building to clear nearby obstructions and to get a good signal. In which case installing a satellite dish would be far cheaper than hiring a cherry picker to install a TV aerial.