Well, like it or not nowdays we are forced to use credit cards on internet specially if we want to buy htpc stuff, since this are kind of rare objects. Internet has great offers and really nifty prices.
On the other hand a lot of people ,specially in Europe, does not feel secure by using the credit card over the net. I too had the same problems ... Infact the use of an credit card over internet could become a problem.
So what is the solution ?
Well the safest solution is to use an special credit card only for use over the net. A lot of states offer some special pre-paid electron credit cards. These cards are really usefull for internet use. Some of them are richargables too.
For example in Italy there is the postepay card from poste.it. This is an prepaid/richargable credit card !
Another example, in Greece this time, is the giftcard from the bank of Attica.
In America there is the giftcard from mastercard but i never used this card. You can still try it.
An good tip after getting an credit card is to use some internet services like paypal. By adding your card on paypal you can use directly your paypal account with some "paypal" shops. This is safer and easier.
Another way is to create an visa/mastercard and use it only for internet. For more security you can add it on paypal and use paypal in order to do all your shopping.

---

So we talked about credit cards, but what about the internet security?
Even if we use an safe, prepaid, risk free credit card, but we use an hacked computer over the net our personal informations could be at risk !
So what we can do in order to make secure eshopping ?
First of all the pc which is beeing used to do shopping must have :
1) An active Firewall
2) An Anti-Virus/trojan system
3) Rootkit protected
4) An good browser

Your pc must be clean and protected in order to do shopping :)
1)Let's start with the No.1, the firewall. I recommend the firewall of windows. Just enable it! If you want an better firewall you can try the free version of zonealarm

2)As good and free antivirus i consider avast. Another free and good antivirus is the antivir
An good site that tests antivirus every 6 months is virus.gr

3)Now many of you will say 'what the heck is the rootkit?'
Well the rootkit is evil method that bypass the OS in order to render ,itself and other files invisible for any operating system. Just think about it, if even the operating system does not see these kind of files how can an antivirus see them and clean them? It is impossible ! Sadly i saw that huge companies like Sony use rootkits in order to spy their users. Read more here (sysinternals)
Now that you understood how important is to scan your computer to find rootkits i suggest you to scan your computer with rootkitrevealer It is free !

4)An good/safe browser is always a good friend of security.
I suggest to use firefox or opera. Do not use internet explorer. Internet explorer has many many bugs and can be easily hacked specially on an not updated system.
When you made an order make sure that your browser is on an secure page . An secure page has this symbol on the bottom right of the browser. If for any reason this symbol does not appears do not make any order and furthermore do not give any information about yourself !!!

If you read carefully this article i'm pretty sure that you can do secure online shopping without risks.
Good shopping !!!