I was diagnosed T2 whilst working in Ireland.m My GP visits cost me 50 euros a time and blood tests 30 euros every time. This was back in 2013 so prices will have gone up.
I did manage to get an LTI card which gave me my strips and tablets free, but other prescriptions still had to be paid for and in order to keep prices down I had to shop around at chemists as the price could vary, even for the same drug.
I was looked after by the local diabetes clinic at the hospital who were pretty good, however to the incredible lack of info at diagnosis I largely took responsibility for sorting out my own health management, rather than rely on the medical profession.
Even then the medical services were over stretched and there were reports of people working overseas year for ops and excessive time spent on trollies.
People are strongly encouraged to take up insurance for health in order to get looked after quicker. I had it through work, but was lucky enough not to use it.
Don't rule out going to Ireland, but I do recommend you get your health under control so that you don't arrive and put yourself under stress of dealing with a medical system under severe strain.