Not so much a bargain but a lot of people may not realise this....and is sort of a bargain if you can take advantage of the backlog situation :)
"Section 5 of the Customer Charter - We aim to ensure that the average lead time for an appointment at an individual NCT centre is less than or equal to 15 days. You will be provided with a test, free of charge, where an appointment cannot be offered within a 28 day period"
https://www.ncts.ie/customer-charter