GIMP is very similar to photoshop but free.
 
I've started painting stuff on my computer again and I wanted a nice challenge to bring back my old skills. I want to do a Starcraft marine since I love doing power armour and I've never done a Starcraft marine before. I'm not a huge fan of the games but I love their power armour design. It will probably be a full colour artwork. Here's my early work in progress pic: