Greasemonkey

Greasemonkey, also known as grees@ is yet another usefull Firefox extension.
Here's a description from official Greasemonkey site:

Greasemonkey is a Firefox extension which lets you to add bits of DHTML ("user scripts") to any web page to change its behavior. In much the same way that user CSS lets you take control of a web page's style, user scripts let you easily control any aspect of a web page's design or interaction.

You can install Greasemonkey from this page!

What we are interested here is, how can it improve your Ogaming.
Most common uses (scripts) are:

• Directly send recycler, spy a planet or moon from galaxy
• Removes commander ad, and other ads
• Removes Commander info from left menu
• Show colored alliances in galaxy panel, variable size of debris field icon, adds arrival time to flights overview...

You can download Ogame scripts for Greasemonkey and install them just few clicks. No need to pay for Commander anymore.
If you're a bit advanced user, you can make a custom script yourself and add even more functionality. Diveintogreasemonkey.org can help you with the first steps.

I am unsure whether Greasemonkey is legal or not, you should contact GO's in your universe and ask. But even if it's not legal, there is no way you can be tracked if you use it.