The products that salons sell aren't necessarily good for your hair - even the ones that are supposedly made specifically for hair replacement systems. They are high-profit add-ons that salons love to push.
The most important product is shampoo. It needs to be 100% sulfate free, otherwise, it will dry out your hair quickly. Any good conditioner is okay because your hair will absorb only as much as it needs. I don't advise using "leave-in" conditioners, but some people like them. You'll also need a hair serum which will coat and protect the individual hairs and help to prevent damage from shampoos, water, styling products, etc.
You absolutely need to avoid any hair spray that contains alcohol - and most of them do.
The best products I have found are made by Loma Pearatin. Their products are excellent. To keep my hair color from fading and oxidizing (turning red/orange), I use Back2Natural color conditioner.