I'm so glad you're asking for advice on this because binding can be VERY DANGEROUS if it's done wrong. 1) NEVER use ACE bandages, or any type of bandage for that matter. It can cause serious damage to your ribs and your lungs and your body ends up growing around it, causing deformities. 2) Sports bras are safe! But they tend to only work for smaller breasts. If you have larger breasts or end up growing, you'll need a true legitimate binder. 3) Binders are indeed the best option to get the flattest chest and they are also designed to be safe. They are also not that expensive! Definitely worth the money to get one you really like and is comfortable because you'll be wearing every day. Here's a link with great advice. It also has some links at the bottom to places you can get safe binders at. Chest Binding 101 - FTM Binder Guide | FTM Binding, Chest Binder, Breast Binders
