You don't need a machine to do lunges. First work on your form without weights. Then all you need is a dumbbell in each had. There are also things called power bands that you wrap around your outer thighs or ankles and they had resistance. Just remember "butt back", ankle and knee stay in align, forming a 90 degree angle. You should be able to pull your toes up off the floor if you are doing them right...goes for squats too.

If your gym offers fitness classes, get in there and do a kick boxing class...great for the legs.

lunges, lunges, lunges and lots of cardio, and of course eating well! I have always had larger thighs and after doing a million lunges I have legs that people complement me on now. I joined a Jazzercise class which incorporates both lunges and cardio. it was the best thing I ever did. The machines are great for toning but if you have large thighs and you use machines they will get somewhat larger but more toned so you need both all three; cardio, strength training and diet...the holy trinity!