Ok. The swimming prosthesis are cheaper. Have a look at these. And also some great cheaper version front clip bras are on this site.that I still wear exercising as I don't really need super support since recobstruction.
https://www.erilan.com.au/collections/mastectomy-prostheses?page=2Target did have some front zip bathers that had pockets so you never know. I bought this one from speedo though in expectation I'd need a breast form (I didn't ). It was apparently designed by someone who had a mastectomy and radiotherapy and didn't want too much on show.
http://www.swimmer.com.au/speedo-black-spirit-womens-one-piece-swimsuit.htmhttp://www.swimmer.com.au/speedo-spirit-turbo-stradbroke-womens-one-piecehttp://www.swimmer.com.au/speedo-spirit-turbo-frosted-fire-womens-one-pieceAlso...a shelf bra type might be suitable also but you might need to try on. My pool sells them so you can look. But this might be suitsble as it has shaped cups inserted so you could utilize the pocket to secure the prostheses.
Although I believe some aqua ones adhere to you...so as long as a suitable tight shelf bra one might cut it.
http://www.swimmer.com.au/zoggs-renaissance-womens-one-piecehttp://www.swimmer.com.au/zoggs-cairns-sirenetta-womens-one-pieceI've never worn a prosthesis so I'm sure other ladies will provide more detailed advise as will your fitter.
The speedo and zoggs range are very good quality and if cared for properly will last for years with no fading in chlorine. I get 2 to 3 years usually.
Kath x