A few weeks ago, Samuel bought 5 apples from his local farmers' market. Today, the number of apples Samuel bought was 40% lower. How many apples did he buy today?

If Samuel bought 5 apples, the 40% lower amount today is 40/100 * 5 = <<40/100*5=2>>2 apples.

The number of apples Samuel bought today is 5 - 2 = <<5-2=3>>3 apples. Answer: \boxed{3}.