If we limit it to 5. And we’re talking about notes that you could feasibly afford. You might need to dip into your savings or save for a few years or take out a loan. Not talking about notes that go for €1,000,000+ at auction.
Choice 1 and 2.
The first banknotes issued in Ireland, after private banks, were called Ploughmans. They came in £1, £5, £10, £20, £50 and £100 denominations. The £20, £50 and £100 were all recalled and there has never been any found out in the wild. So if you want them the only option is to get the De La Rue colour trials. Here are some examples.




So my first and second choice would be a £20 and £50 De La Rue Plougman colour trial.
You are talking about €3,000 to €4,000 each at auction.
Choice 3 is the Da Ming Baochao.
These were Ming dynasty banknotes that were issued around 1375. As far as I know they were the first mass produced banknotes. I’ve seen examples go for around €2,500 at auction.
https://en.wikipedia.org/wiki/Da_Ming_Baochao

Choice 4 and 5 is the US silver certificate educational series.
I really like banknotes with the classical style allegories. I think this series has some of the nicest examples of that style.



So my fourth and fifth choice is the $2 and $5 Silver certificate from the educational series. From looking at Ebay I think a really nice example of each note would cost €1000 each.

