I’m so pleased to learn that you and your classmates are learning Chinese. I’d like to recommend the following two dictionaries. The English-Chinese Chinese-English Dictionary is really a good one for beginners. It has 18,000 English words and 20,000 Chinese words. Besides plenty of examples, it has many notes telling you how to use a word. Xinhua dictionary is the most popular Chinese dictionary , and it has a vocabulary of 10,000 words. It may also be useful to some advanced learners of Chinese. Of the two, ECCED is the more expensive, costing 52 yuan, and XD costs 11 yuan.
Please let me know if you want me to buy these dictionaries.