I dont have money to buy photoshop, is there a free alternative?

The answer is GIMP. Gimp is an open source image editing, creation software widely used in linux platforms and is also available in windows. The strength of gimp comes not only from its basic features which are very much in league with adobe photoshop for a simple webmaster or web user, but also the wide range of plugins available for it. Since Gimp is open source, the plugins are developed by the community and are free (you may find an odd paid plugin).

The plugins provide so much strength that gimp can easily be used as an alternative to commercial softwares adobe photoshop, corel draw, paintshop pro. Although some people do suggest that gimp may not provide professional level of finesse which the commercial software provide. But for my usage, I have found gimp to be quite sufficient.

Some of the coolest plugins for me:

Watermark

Aqua Bou

Find more at Gimp plugin registry.