I've been using the take and toss kind for more than two years now (the same ones). If my kid really chucks it, the lid may come off, but I don't generally have any sort of leaking problem.
Also, I enlarged the drinking holes (with a hot paperclip) to give it better flow...most sipply cups are just glorified bottles and I cringe to think of what effect they can have on their teeth. I even cut the valves out of her straw type cups that go to daycare.
I started my daughter on a cup at 5 months. Your daughter is certainly old enough to manage it ok. Start with water until she gets the hang of the flow.
But, if you don't need them, use what you have. Don't spend money that you don't need to.