Irish prisoners have nearly €750,000 in their bank accounts.
Every inmate receives daily pocket money from the Irish Prison Service (IPS), which can be used to buy non-essential goods such as computer games and tobacco.
However, they can also save their allowance, and can earn more by doing chores.
Records released under the Freedom of Information Act reveal the bank account holding prisoners' private funds had a balance of €734,117 in October.
Unspent money is given to inmates on their release.
A total of €2.8m in pocket money was given to prisoners last year, representing a 10pc increase on 2017.
Before 2012, all inmates were entitled to a flat-rate of €2.35 a day.
An incentivised regime was then introduced, allowing money to be raised or reduced, depending on their behaviour.
A standard rate of €1.70 now applies, but this can be increased to an enhanced rate of €2.20 if a prisoner is compliant, or cut to a basic rate of 95c if they misbehave.
The prison population as of last May 1 was 3,996.
The proportion of inmates on the basic rate grew from 9pc to 11pc last year.
However, the number on the enhanced rate also climbed, from 46pc to 48pc.
Around 41pc of prisoners were on the standard rate last year, compared with 45pc in 2017. Inmates can earn an extra €3.50 a week for chores.
In addition to spending on tuck shop items, prisoners can use the money to pay for extra services.
In-cell TV costs 15c a day, while digital packages are also available.
The IPS had spent more than €325,000 providing Sky Sports and other premium channels over the past four years.