G'day Allrounder,
I assume that you are going to Shannon as the rent in Dublin is generally higher than 800 per month.
I am currently in Melbourne Centre and have been offered a job in Dublin starting in October.
Have a look at this site for health insurance, we found it fairly useful.
Health Care Ireland. Health Insurance Ireland. Vhi Ireland
For used cars this is a handy site.
Car Buyers Guide - Buy & Sell, New & Used Cars in Ireland with CBG
It looks like used cars are pretty cheap in Ireland but you have to be careful with the taxes. I have been told that it is better to go with a Diesel car as the taxes work out cheaper.
Cheers,
West ATC