Masonry can be cut by using several methods and as most cut edges can be hidden by mortar etc. the cut edge does not need to be perfect.
The cheapest way to cut masonry is with a bolster chisel and heavy club hammer, this requires some practice to get it right but is not that difficult. When cutting masonry it is essential to mark the object to be cut an all four sides and it is also important to either have the object so that it is in the air or led on a thick bed of sand, this is because when you hit the chisel with the hammer the shock waves bounce right through the object and can cause it to break unevenly.
All masonry can be cut with an angle grinder and disk, personally I would never use an abrasive disk as they are dangerous and have been known to disintegrate! Diamond tipped blades are far safer and cut far easier, with less dust.
Here I am going to cut a length of a 2" thick concrete flag. Firstly mark a line where you require it cutting.
Then support the object to be cut with some suitable pieces of wood, so that it is off the floor.
Then you need some personal protective equipment, just out of camera shot I have a dust mask and goggles on although I forgot the gloves! If working inside ear protectors are also advised.
Never force a blade, let it cut through slowly and evenly. You can soon master perfect cuts with an angle grinder. DO NOT put the grinder down until it has stopped rotating completely!