The Penny(p) and the Pound(£) are basically the units of currency today. The plural of penny is either pennies or pence. 100 pence make up a pound. At the current exchange rate a dollar is about 65p. £1 is therefore about $1.5.
Current coins and notes include 1p, 2p, 5p, 10p, 50p, £1 and £2 (coins) and £5, £10, £20 and £50 (notes).
Older people will often use traditional names or corruptions of currency terms which seem now to be sadly going out of fashion. Thus two pence may be called 'tuppence' and three pence 'thrupence'. A pound may be called a 'quid', so £10 would be 10 quid (but some young Brits may not know these terms). There are also slang terms traditionally used in certain parts of the country such as Cockney rhyming slang in London, but even most Londoners would not know these.
The old currency of Britain was pounds, shillings and pence, but this was all changed to decimal currency in the 1970s.