"iDeal" is a secure online payment method designed by the major dutch banks: (wiki)
http://en.wikipedia.org/wiki/IDEAL
It neatly and securely meshes from the Online shop site, into the different online banking systems of these major banks.
So unless you buy it at a online store that has a consumer focus in the Netherlands (
www.bol.com would be my first guess) then you're not likely going to be able to buy that way.
An alternative payment option I know of is common all over the world is Paypal.: (in dutch)
https://www.paypal.com/nl/cgi-bin/we...PayPal-outside
It seems you can use it with an ordinary bankaccount, as opposed to only with a creditcard. That wasn't possible when I opened my paypall account years ago. So it don't have much experience in how safe that particular option is. Basically, to pay for something, you choose the Paypal icon on the site of the online shop. And eventually when the payment is supposed to be done, the site opens up a secure transaction (over HTTPS) to the Paypal site for you to confirm the payment. You authenticate with username and password, so make sure it isn't a simple one to crack. With iDeal you have additional challenge codes (from TAN tables or SMS, or from these special calculator thingies) to verify you are the right person. Which is I guess a bit saver than Paypal. You or your parents have to make a trade-off is you want to risk it. But nobody can guarantee 100% safety. When the payment is done, Paypal simple deducts the amount (after currency conversion) from the creditcard/bankaccount.
But finding an online shop that actually can supply a copy of SH4 1.5 to the netherlands is difficult indeed. I've seen a lot of long delivery delays at the various online shops, suggesting the game is well out of stock. Well a year ago or so.