Look at the Buck Model 105 Pathfinder. It should be legal, but check blade length laws. Blade is five inches.
Pretty sharp and tough; good sheath.
I gather that Wal-Mart sells Buck pretty cheap. This should be about $40 or less and is a very good outdoors and defense knife that doesn't look "tactical" if some cop is trying to decide if he wants to bust her for carrying a knife for hurting people. Image counts.
If money is no object, look at the Fallkniven S-1. Sheath options. Very sturdy with a firm grip handle. But the VG-10 core steel is harder to hone than a Buck. Cost in the USA should range from $125-150.
www.fallkniven.com A superb camp, trail, and hunting knife.
Also excellent are the older Puma Hunter's Pal and Outdoor models, but they've become collectible.
Value for money, get that Buck. It's all she'll ever need and looks good and feels good in the hand. I think Buck will make one up with a white handle, if she'd prefer that to the usual black phenolic.