To get $1 for 1 pip, you need to open a mini account and trade minilots (10,000 units) . Note that the $1/pip for 10,000 units is only for pairs with USD as the quote currency. For example: EUR/USD, GBP/USD, or AUD/USD.

Leverage determines how much margin you need to enter a trade. If you select 1:100, you need $100 margin for 1 minilot. If you select 1:10, you need $1,000 for 1 minilot. So: margin = lot size * leverage.