I am also a c-cup. I had a single mastectomy nearly 5 years ago. While I have a proper prosthesis, I rarely wear it. I have an Amoena Aqua Wave swimming prosthesis (much cheaper than the $400 ones) which I wear almost all the time both for swimming and in my sports bras. I just find it works best for me. I swim a lot and have a couple of mastectomy swimsuits which I bought soon after surgery. They are still in very good condition despite almost daily use in summer. They were expensive but I have well and truly got my money’s worth. I only wear the more expensive prosthesis occasionally but this might just be my casual, active lifestyle.
As you can see, different situations for each of us and what suits one person might not work for everyone. Take care. xxx