Question about wordpress from a newbie

I'm a newbie that even know nothing about any programming knowledge.I just want to write blogs with wordpress.
Question:
1.Is wordpress really free?What's the paid wordpress hosting?Many paid themes there so I need to buy them if I want my blog looks cool?
2.Do I have to pay for traffic and domain?
3.I have seen a wordpress installation tutorial which tell me I have to download and install xampp first.But I haven't seen that on the official site?

Wordpress is totally free,but you may want some premium themes to make your site looks professional while there are many free themes.You need hosting and domain to install your wordpress blog.

1.Is wordpress really free?What's the paid wordpress hosting?Many paid themes there so I need to buy them if I want my blog looks cool?
Yes wordpress is free to use as like blogger but about wordpress is far far better than blogger and yes they do have themes which are good but as per new guidelines of google algorithm, check themes properly and adsense tos if you ar eusing it..
2.Do I have to pay for traffic and domain?
As I said wordpress is free like blogger or if you have domain and hosting you can create a good looking website with wordpress with the help of fantastico software which is available in hosting cpanel..
3.I have seen a wordpress installation tutorial which tell me I have to download and install xampp first.But I haven't seen that on the official site?
I don't have much knowledge about this but you can look for hosting cpanel if you are using hostgator for hosting..

Yes Wordpress is free and at the same time paid also. You may choose which ever is appropriate for you. Let me tell you in detail.

Like if you make a blog 'myblog.wordpress.com' then it is absolutely free. But if you want to make blog like 'myblog.com' then it is not free, but costs $17/year. But considering the services you get from wordpress this $17 is worth paying for a whole year.

WordPress is completely free, but you might want to reward some of the themes to make your site looks professional Although there are many needs themes.You free hosting and domain to install WordPress blog.

WordPress is completely free, but you may want to reward some of the themes to make your site looks professional themes.You Although many of the needs of free hosting and a domain to install WordPress blog.