Emir-says Keyarn Hello Kayarn.. My advice for you is to get a self-hosted wordpress from Reliable web hosters..
The first link Weezy posted for you discussed the disadvantages of using a hosted wordpress blog in which your url will be something like sitename.wordpress.com and also most themes and plugins are premium.. So get a self hosted from webhosters like Namecheap.com , Hostwinds Godaddy and many more...
HOW TO UPLOAD THEMES
you can do this in two ways namely:
1. Through your ftp client
This is only accessible if you used a self hosted blog whereby all Cpanel, Databases and Ftp details will be sent to you after your order.
2. Using your Wp Admin Dashboard..
Steps
Logon to your dashboard i.e sitename.com/wp-admin
then Goto Appearances You will see the default Theme after the page opens then Select Add New
Lots of Themes will be displayed to you here, You can Install and Activate anyone you like here..
But if you have the theme you want to use with you, Make sure it is in a .Zip format i.e ThemeName.zip
Then Click on Appearances >> Add New >> Upload then select the Then from your filemanager and Upload.. A page will opens after Uploading, Then Click Activate.. That's all
Still have issues, Reply Here or Here