Annie plans to grow vegetables in her backyard. She wants to grow onions and tomatoes,and plans to buy 6 times as many onion plants as tomato plants. Tomato plants cost $0.99 each and onion plants cost $0.08 each. Annie has $60 to spend. If Annie buys exactly 6 times as many onion plants as she buys tomato plants, how many onion plants can she buy without going over $60?