You need to buy them on the day they IPO. You will not be able to buy it at the IPO price but at the price of the first minute of trading.
On top of that, "a couple of hundred €" is probably not enough money. The fees to buy stocks on the Nasdaq is usually in the tens of euro. You'll probably have between 10 and 50 euros of fees at the cheaper online trading platforms.
You can also call your traditional bank to buy the stocks but the fees would probably be higher.