Irish prisoners were paid more than €2.5 million in pocket-money in the first ten months of last year.
According to details released under the Freedom of Information Act, inmates received a further €4.3 million in gifts from their family and friends in all of 2019.
There are more than 4,000 prisoners in 13 jails across the state.
Every inmate receives a daily allowance from the Irish Prison Service which they can spend to buy items in the tuck shop.
The standard daily rate is €1.70 but this rises to €2.20 for well-behaved prisoners and is cut to 95 cents for bad behaviour.
Inmates can also get additional payments of up to €3.50 per week for working in areas such as prison kitchens or laundries.
In the first ten months of last year, more than €2.5 million was paid under these schemes.
John Lonergan, a former governor of Mountjoy Prison, says the daily allowances are far too low.
"The basic one is less than €7 a week per prisoner and the second grade is around €11 per prisoner a week," said Mr Lonergan.
"But when you take it that a pack of cigarettes alone would cost around €11, I think that puts it into perspective.
"The global figure is misleading the sense that it is a gross figure and the public might feel that that is a huge amount of money but in actual fact it is a very, very tiny amount of money."
In all of last year, prisoners received a further €4.35 million in gifts from family and friends.
Inmates in the country's largest jail - Midlands Prison - received nearly €871,000 while those in Mountjoy Prison - the second biggest - got more than €805,000.