If you need more than a hundred trees, Speedtree will soon be cheaper indeed. There are a lot of textures to be found on the web, and you can make your own. Or use the textures that go with XFrog if you have them. Speedtree also has the possibility to make custom leaf-objects in another app like Lightwave, say a set of UV-mapped planes or even apples, that you can add as leaves in the tree.