nickel

There are two spellings for this word and both are ok: nickle or nickel. The more common spelling these days seems to be nickel. There aren't so many idioms or sayings with associated with this coin but I will cover those I found.

Don't take any wooden nickels.

This is a saying used when someone leaves meaning be careful. It is pretty old fashioned and to be honest I have never heard it used in my life! It means: 　気をつけて。 It comes from counterfeit coins being used in the 19th century made of wood, so you are telling someone to be careful not to get any fake money.

nickel-and-dime

This means very ordinary and not important, it is not such a common usage.

That town is full of nickel-and-dime shops.

Meaning it is full or ordinary shops that are not interesting.

to nickel and dime (someone)

This is probably the most common nickel idiom and it is one of my pet peeves. I HATE it when companies or stores do this to me. This means to charge someone many small amounts for something or to charge you a small amount of money as an extra fee.

For example;

I went to an onsen in Tsuwano and the fee was really low but then I had to pay extra for towels, soap, shampoo, etc. They nickel and dimed me~! But in Korea, when I went to a jimjilbang(bath and sauna place) they charge a higher entry fee but everything is included: towels, robe, shampoo, etc. I prefer the second system, how about you?

Also, recently airlines are nickel and diming us, especially in the U.S. The airfare is cheap but then there are a million extra fees! Fuel surcharges, taxes, airport taxes, baggage fees, pay for your in-flight meal and drinks, pay for the headphones, etc.