In general resistance bands are heavier and need more strength to pull than do stretch bands. Resistance bands are measured by the force need to double them in length i.e. a band rated at 30 pounds requires that much weight to double it in length. I have not ever seen stretch bands rated as to their level of resistance. Resistance bands normally have some form of handle which makes them easier to use and many have interchangeable bands allowing the user to increase or decrease the resistance for different exercises.
You can purchase a three band set with handles and a DVD from Walmart for about $15 USD which makes an excellent beginning set. You can add or subtract bands from the handles as you choose for different exercises.
It is called WORK-ing out for a reason.
I said getting fit was simple, I did not say it was easy.
Cardio burns calories, strength work burns fat.
Eat well to lose weight, exercise to get fit
You can not build a six pack using twelve packs
Often when we seek a magic bullet for fitness we end up shooting ourselves in the foot.
"I think calories are little germs in food that all moms are afraid of" Dennis the Menace