title: USPS shipping rate API limitations
body: <p>I am working on showing the shipping rates on the product pages, like in Amazon and eBay.</p>
  
  <p>However, because I'll be calling the API a lot more then the usual cart page, I am wondering if there are any limits to USPS API that can prevent me from using the API on product pages? </p>
  
  <p>Do you think I should use some kind of offline processing?</p>