The value would depend on the year and condition, but most Irish coins aren't worth much unless they're part of a mint set.
1p
Prior to 1971, 1p was known as 1d. They would have very little value. They are no longer legal tender, but a lot of Irish homes would have them and people who visited Ireland up to 1971 may also have them.
See the link below. It shows a 1980 1p, but other than the year any Irish 1p from 1971 to 2001 would look the same.
Ten 1p coins Eight 1p coins 2p coin Six 1p coins two 2p coins Four 1p coins three 2p coins Two 1p coins four 2p coins. Two 5p coins One 5p coin two 2p coins one 1p coin One 5p coin one 2p coin three 1p coins One 5p coin five 1p coins Five 2p coins One 10p coin
Such a coin does not exist. The Irish 10 Pence coin was first issued in 1969.
Very little, probably £1 to £2 max.
All Irish coins have the word "Éire" on them. The value depends on the condition and the denomination.
The mass of an English penny coin is 3.56 grams.
A British 2003 Uncirculated coin set (10 coins - £2 to 1p) could fetch up to £14 GBP. A British 2003 Proof coin set (11 coins - £5 to 1p) could fetch up to £34 GBP. It should be noted that the value of any "coin set" is dependant on it being in its original packaging and condition. A reputable coin dealer will be able to give a more accurate valuation.
1p
From decimalization until 1991, the 1p coin was bronze. From 1992 onwards, it has been copper plated steel.
An Irish "Millennium" coin, with a face value of one Irish punt (or "pound"), is worth about US$7.50 in Uncirculated condition and about US$8.50 in Proof.