This frugal fitness core exercise set can be done without any expenses or equipment.
Crunches-lay on you back with your legs bent, with hands behind head raise your upper body towards the ceiling, repeat 30 times
30 rope climbs-while laying on your back with your legs bent, climb an imaginary rope and lift your upper body, repeat 30 times
30 side crunches-while laying on your back with your legs bent, cross you left foot over you right knee, with your hands behind your head, raise your right elbow to left knee, repeat 30 times and then switch to right foot over left knee and left elbow to right knee.
Planks. While facing the floor balance your body on your forearms and toes lowering your stomach to the floor. Hold for as long as possible.
Are you at seated at a desk most of the day?
You might consider using a Gaiam Balance Ball Chair for the time you are spent sitting at your desk or really anytime. The ball forces you to use your core muscles to maintain your balance.
I prefer keeping my regular chair in tow for times when I need stability and can relax my body fully however I keep my ball chair stowed nearby for times when I feel like I need to tighten and need to activate my abdomen muscles.
Your body frame is part of your beauty. Your waist, back and hip strength are the key components of a beautiful core.