Welcome, Echoluv!
My recommendation would be to shop around on Amazon for a scale. There's a lot more variety on there than in a store, with the added benefit of being able to check reviews and order from the comfort of your home. Remember that knowing your weight is a tool in your journey toward health, and that whatever that number is, it shouldn't dictate how you feel about yourself.
Couch to 5k is a great program, even for us larger ladies. And it's free! Utilizing the program, I was able to gradually get to a point where I could jog for a full 30 minutes without stopping. Which, at over 300 lbs, I never thought I would be able to do. I would suggest you start off gently and make sure you have good walking/jogging shoes.
We've all been where you are, and we know the struggle. That's one of the reasons why this group is so supportive and wonderful.