Although the British Five Pound coin is legal tender, it is intended to be a non-circulating commemorative. In their year of issue, they are available from the Royal Mint and can be purchased on line. Subsequently they can be purchased from a coin dealer.
Some banks produce a commemorative Five Pound coin, but these are not legal tender and are more of a souvenir.
The Gibraltar Five Pound coins are similar to the British Five Pound coins in that although they are legal tender, the Five Pound coin is not intended to be a circulating coin, but a collectible of a commemorative nature and many businesses are reluctant to accept them. Gibraltar currency is only legal tender in Gibraltar and most authorities advise changing your currency before you depart Gibraltar. If you want to sell your Five Pound coin, take it to a reputable coin dealer.
Although it is legal tender, the British Five Pound coin is not intended to be a circulating coin, but a collectible of a commemorative nature. Many businesses are reluctant to accept the Five Pound coin, but the Post Office has a stated policy of accepting Five pound coins for goods and services.
Banks don't buy old coins, coin dealers will buy old coins, some jewelry stores will buy old coins, banks will take your old coins at face value and then sell them to coin dealers and and make some profit.
Some banks do sell American Silver Eagles, but they do not hold and sell silver coins that are turned in.
Banks will happily buy gold coins for their face value - since this is nearly always far less than they are actually worth. If you wish to sell your coins for their actual value, take them to a reputable goldsmith.
You can sell it for a Laramie in Salt Lake City Utah!
To buy? You can buy them for $1 at many banks, they are not rare coins, simply unpopular coins.
Most do not. Gold coins can either be purchased from the US mint (if you want modern US bullion coins), reputable online sites such as APMEX, or your local coin and some jewelry stores.
If you are talking about a US coin, you have to go to the US mint website to buy silver coins. Banks don't sell silver coins. They don't distribute them either.
No, banks do not usually buy silver coins. However, you can always go to a silver and gold dealer and exchange your precious metals for hard cash there.
These 1992 Olympic gold coins currently sell for about $275
Most do not. Gold coins can either be purchased from the US mint (if you want modern US bullion coins), reputable online sites such as APMEX, or your local coin and some jewelry stores.