A PayPal account? Why do I need a that one? Normally when you buy anything from any webstore you can just pay your things in online bank directly. I just wonder if you can do that with Steam which isn't actually a webstore. I have never heard anything like PayPal.
How does the paying via PayPal work?
And another question is that I saw there's "Visa" in the opinions but does that work with "Visa Electron" card?
That's the problem, I don't think Steam accepts direct transfers from bank accounts.
As for PayPal, I think you are better off googling the answer. I can't provide a very good description.

Also, I think any card with a Visa logo will work. No harm in trying.