You are going to have to give a few more details, especially the country of origin because there are multiple currencies called the pound and there are no British 1 pound coins issued that year (they weren't made until 1983), so please post a new question either giving the country of origin or giving enough identifying details that someone could help you identify your coin.
1 pound
The face value of an Eire 1 penny coin is 1 penny. It was equal to 1/100 of an Irish pound before the euro.
As I type this the value of 1 pound of gold is $18,040.00
A 1979 Susan B. Anthony coin is worth 1 dollar (face value) still to this day unless in a condition that is UNC.
A 1 pound Silver Eagle is worth about $200.
A £5 coin is the exact same value as a £5 note or 5 £1 coins etc
In the UK the most common high value coin is the one pound coin (£1) we do have a £2 coin in circulation but it is not popular, we also have commemorative five pound (£5) coin but they are for the collectors and not in general circulation. If you want a more specific answer related to a particular country then you need to ask a more detailed question.
The coin you are referring to is likely the Susan B. Anthony dollar coin, which features a depiction of the suffragist Susan B. Anthony on the obverse and an eagle landing on the moon on the reverse. These coins were minted from 1979 to 1981 and then again in 1999. In circulated condition, the value of a 1979 Susan B. Anthony dollar coin is typically around face value ($1), as they are still fairly common.
The Royal Mint issued no 1977 commemorative gold coins.
Currently, British general circulation currency comes in the following denominations - 1 Penny coin 2 Pence coin 5 Pence coin 10 Pence coin 20 Pence coin 50 Pence coin 1 Pound coin 2 Pound coin 5 Pound note 10 Pound note 20 Pound note 50 Pound note
$1 to $7500 depending upon the mint mark, the variety and the condition of the coin.
Many countries have a coin to the value of one unit of currency (one pound, one euro, one dollar, etc.).