Go for the demos. I just bought Zbrush and really like it since it does more than just textures. Both deep paint and Zbrush have demo's. Don't know about Deep paint but Zbrush you can get your demo extended by getting a new number from the company. So gives you a lot of time to play with it. PSP is great. Photoshop is a super program I guess, just think their price is insane.