The most wicked word of this week goes to ‘才’. It can both mean something is very difficult and easy to achieve.
1). 我家离学校很远，骑车半小时才到。(Indicating riding half an hour is a long journey.)
2). 我家离学校很近，才半个小时就到了。(Indicating half an hour is short distance, comparatively easy one.)
If 才 is followed by a specific time period of a specific amount of money, it means ‘only’.
考试才两个小时就结束了。
美国的电脑很便宜，才300块就能买一台。
If 才is followed directly by verbs instead of a specific amount of time/money, it means something is very difficult.
美国的电脑很贵，要300块才买的了一台。
Hopefully it helps clear some of your doubts.
