I've seen some great things done with just a simple basecoat of a foundation and then a Devlun Mud Wash. If you wanted you could add a highlight of the foundation again to lighten up raised areas. For example you could paint your Lizardmen Mordian Blue, with Hormagaunt Purple, Mechrite Red, Knarloc Green, or any other color combo you like and then wash the whole model and pick out details afterwords, IE eyes, teeth, weapons, etc. Its quick, its easy, and you don't need to spend a bucket load on paint. Of course they're not gonna look "fantastic" persay, but they'll definitely pass as >Table Top if you paint them well.
Just be careful to water down your Foundation paints very well as they are much thicker and tend to glob up on you if you're not careful.
Good luck!