Decoys are necessary yo remove the attantion from you (the caller) in some situations and are not 100% necessary.
I've used the el cheapo foam deeks from dic_ks or gander or wherever I find them at...
One thing about calls... have her practice them outdoors... 1, because its annoying as hell to listen to indoors and 2. all calls sound different outdoors than in.
You can tune a call all you want indoors... get it in the woods and suddenly it sounds more like a pheasant than a turkey...
And get her a blind.. then she can wear and do whatever she wants... Blinds are the ultimate cheat to turkey hunting... I had a turkey at 4 feet in one while I was eatin a snickers bar and my kid played some game on my phone...