The cost of replacement parts varies depending on which part is needed, but can range between $3 and $40 depending on where the parts are purchased from and the brand. If the replacement parts are for what would be considered a public bathroom, the industrial or universal flush valves can be several hundred dollars depending on if they are manual flush or if they have a motion sensor.
Most standard home repairs are fairly simple and require few tools, but can be time consuming. The most commons repairs are the valves and the wax rings. Both of these repairs require the water to be removed from the toilet, but the wax ring will mean that the toilet has to be lifted from the floor.