I use various flavours of Blender and Gimp (both free and regularly updated).... unwrap various parts, using "project from view" and scale them, if possible, on a single texture sheet, that contains all the various colours/detail required for the model. You can use very small bits of colour for textures (but preferably for low detail items, they get too grainy). High detail parts need a bigger bit of your "Texture Map"...shiny bits and dull bits are made using a diff. material...but the same Texture Map....you'll be surprised what can be squeezed out of a single map. The original idea, for "mini textures", I learnt from Paul Hobbs...Micro Textures, used in his Trainz Tutorials, http://www.44090digitalmodels.co.uk/
have fun, regards.