The trash cans that are so expensive are expensive because they are made of stainless steel or other higher quality materials.
Also some people will gladly pay a higher price for a nicer looking trash can and so the manufacturer or place selling the trash can will raise the price because they know the person will pay for it.
I bought a nice high quality good looking stainless steel kitchen trash can which looks better in my kitchen than my old cheap plastic dollar store trash can did.
You can find cheaper trash cans but they may not look as good but they will still function just fine.
The standard size trash cans are between 10 to 13 gallons in size.
Some people have larger kitchen trash cans than others depending on how much kitchen trash they produce.
My kitchen trash can is 13 gallons which is large enough for me.
I have a large trash can I keep out in the garage that I then put the kitchen trash and other trash in.
Then that trash can goes out to the street for trash pick up on Mondays.
I empty my kitchen trash can every few days which is enough for me as we don't produce all that much trash.
My trash can has a foot pedal and a lid that seals in any smells so I don't smell anything from the trash can.