This question is a great example of how we can save time by applying GRE-specific strategies.

First, once we finish reading the question, we should scan the answer choices.
Here, we see that the answer choices are VERY spread apart, which means we can be quite AGGRESSIVE with our estimation.

Given: Bottle R contains 250 capsules and costs $6.25
So, the cost per capsule = $6.25/250
Tip: Dividing a small number by a larger number is a pain, and there are plenty of opportunities to make mistakes. To avoid mistakes, we can simplify matters by converting dollars to cents.
We get: cost per capsule = 625¢/250
Since 500/250 = 2 and 750/250 = 3, we know that 625/250 = 2.something
In other words, the bottle R capsules cost 2.something CENTS each.

Given: Bottle T contains 130 capsules and costs $2.99
We get: cost per capsule = 299¢/130
Since 260/130 = 2 and 390/130 = 3, we know that 299/130 = 2.something
In other words, the bottle T capsules cost 2.something CENTS each.

Since 1 bottle R capsule costs 2.something CENTS , and 1 bottle T capsule costs 2.something CENTS , the DIFFERENCE must be less than 1 CENT (aka $0.01) .

Answer: E