It's initial limit. However, we should clarify that after 15 days of using it will change to $300 per month, so that you'll get a new level of limit. After 30 days it will increase again. So, it will grow rather fast.
Here is info about limits for buying bitcoin via credit/debit cards: https://www.247exchange.com/limits
The main idea is: the longer you use your card with us, the more you can buy.