You can get a cheap piccolo on ebay that would work fine for marching band. It might require some tweaking upon arrival, but I think going that route is more cost effective in the long run. If she falls in love with the piccolo, then I would talk about purchasing a concert piccolo. As with a nicer flute, I would not use a nicer piccolo for marching band. It's hard to justify dropping $1500 or so on a nice piccolo to use maybe for three years in a marching band. You could also look into renting one for the marching season.
Piccolo playing in marching band seemed to me to be a touchy issue back in my marching days. It was a privelege that the best player earned (our director only allowed one piccolo on the field because new piccolo players may not take quickly to tuning it properly--especially to another piccolo). If someone in our flute section had bought a piccolo at random and started bringing it to rehearsal there would have been inevitable onslaught. :P
Imagine my surprise when on my first day at college band camp I discovered there were 26 piccolos and 0 flutes.
