Understanding lighting and costs
To understand what lighting is, first we need to understand how it basically works.
Way back not that long ago actually the only general type lighting was the incandescent bulb… it basically consisted of a glass shape with all oxygen removed and an inert gas inserted… there was a resistive filament that offered resistance to electricity thus creating a current and the result was a wattage .. .. current times the voltage is equal to wattage.. Therefor a 100 watt lamp would basically us about 1 amp of current, but your meter sees it as 100 watt (100 divided by 120 volt is the current) which is seen by the fuse or circuit breaker.. the resulting light was created by the white heat developed on the filament (unable to burn out because there was no oxygen to complete the burnout process) the amount of brightness given off was measured in either lux or Lumen which is the amount of light that can hit the surface of an object… Lumen is basically the metric value of offered light…
The color of the light in an incandescent lamp were mostly all the same.. and it was a yellowish ting what we would understand as warm white.. These lamps usually had a powder coat inserted inside to defuse the light so it would not be hard on the eyes.
This type of lighting was common place in residential situations with some fluorescent for under counter lighting due to its low profile….and if a brighter more consistent light was needed, then the 4 ft by 2 ft industrial type lighting of fluorescent was used…

Fluorescent lighting

Fluorescent lighting is a main stay today.. they were 12 mm in diameter called a T12 lamp and usually came in 30 35 and 40 watt equivalent lighting.. this was related to the amount of light that an incandescent light could put out in lumens.
The fluorescent light came in a variety of sizes and were controlled by a ballast… which in fact is a transformer that kick started the lighting process with a higher voltage then would settle back to run about 110/120 volt to maintain the light level…
How do they work?
The fluorescent tube is a clear glass tube that has the oxygen removed and an inert gas is inserted.. at either end of the tube is a small element that was dipped in a compound that allows EMF (electro motive force) to transfer from one end of the tube to the other this would be considered a plasma arc.. Similar to what you saw in Frankenstein movies or if your familiar with plasma arcs. Like a jacob’s ladder where the arc follows a V from the bottom to the top until the voltage is not enough to continue the arc…
This alone is not enough to sustain light…
When the lamp gets its initial charge, the resulting arc is used to melt a small amount of mercury placed inside the tube… the result of the mercury (I’ll call it a vapour), allows the plasma arc to continue at a lower voltage, which the ballast will detect ( in older fixtures, lamp starters were used, recognized by a blinking until it started)…
The resulting action of this arc is very dangerous to eye and almost no light, so a spray of powder was electrically attached to the inside of the lamp.. this powder called a phosphor, lights up when the UV arc light hits it thus resulting in light.
The different phosphor types gives off a different light, such as warm white ( yellows), to cool white, daylight etc… so the colors go from a yellowish to blueish.. this light look, is called the CRI, color rendering index and is measured in Kelvin.. so if you see a lamp with a 3000K, then your looking at a yellowish, where a 5000K is more of a blue..
The color is the CRI and is and can be used to change your moods and the appeal of how food and other items look..
Without the phosphor, then there would be only an ultra violet stream which is used to kill germs in water treatment or are used in some driers to get rid of bacteria….. same lamp different purpose.
To save on energy costs, manufacturers have come up with a T8 lamp ( 8 mm) in diameter, which allows less power to be used to keep the arc stream going however by my experiences, they don’t seem to last as long as the electrodes at the end seem to get hotter probably due to the size of the area and seem to not last as long. Manufacturers are also now selling T5 ( 5mm).. all use different ballasts to accommodate the power requirements to light the lamps. The older ballasts for the T12 were encased in a tar and once they were nearing their life’s end, would leak the tar out and in some cases start a fire as the tar would ooz out and catch fire due to the heat.. the newer ballasts are an electronic ballast using more state of the art technology not to start a fire.

CFL lights are recognized by the curly glass, and are used to replace incandescent lighting… but use much less power to deliver the same light or similar and allow for the different color levels.
If a 60 watt incandescent lamp uses 60 watts , most of the energy is used up as heat… where the replacement CFL lamps (circuline fluorescent lamp) to give the equivalent of 60 watts of light that the incandescent lamp put out, the power used would be about 15 watts of power, depending.. and the result is a savings of 45 watts of power but the lumen level would be the same..
So why if we are saving so much power, do we need to go with LED lights???

Stands for Light emitting diode. It’s a semi-conductor material that when about 1 volt is reverse biased on the small unit, it tends to create a bit of an arc thus producing light.
One LED does not give enough light for anything other than as an indicator, so manufacturers have produced a different type of semi conductor to produce more light and by using a number of these LEDs can produce a usable light at a fraction of the power cost of a CFL…
Yes there is a transformer in its base to give less voltage and the lamp itself has a number of LEDs installed… however, over time, they will lose their lighting ability.. so when we hear, that they are good for 10 or 20 years, they are not lying but the lumen level will be reduced, an example would be if you purchased an equivalent 60 watt led lamp that uses 9 watts of power, over a period of time, the light will give off approx. 50 watts of equivalent light and degrade until it dies.
OK, so  you are asking, why on earth would I want to spend the high price of an LED lamp when CFLs are cheaper and Incandescent are almost free… well, the incandescent are being phased out due to the power hunger of these lamps and the CFLs are not lasting as long as stated due to the heat produced by the electrodes, thus self-destructing.. but the main issue is the fact that they contain mercury and are not supposed to be discarded in the garbage plus they cost a fortune to recycle and no one really wants to… resulting in the newest lighting, the LED lamp.