Amazon for the first time in more than a decade has raised the minimum order amount necessary to quality for free Super Saver shipping. Previously, customers had to spend just $25 to get free shipping but moving forward, customers will need to buy at least $35 worth of merchandise to quality for free shipping.

It’s unclear exactly why Amazon made the changes although increased shipping costs and an opportunity to promote its Prime service as a more attractive option are two likely reasons.

The online retailer is quick to remind shoppers of their Amazon Prime membership. For $79 per year, subscribers have access to free two-day shipping on more than 15 million Prime-eligible items with no minimum order size. What’s more, Prime members have access to Prime Instant Video which contains over 41,000 movies and television episodes and 350,000 books to borrow through the Kindle Owners’ Lending Library.

The company has been offering a 30-day free trial of Prime for some time now so if you haven’t tried it, you can do so free of charge for a month to see if you like it.

One word of warning, however. Amazon recently changed the price of one-day shipping and Saturday delivery for Prime members. Overnight shipping used to cost $3.99 per item but pricing now varies based on the item’s size and weight with rates starting at $2.99 per item. Saturday delivery now starts at $7.99 per item, we’re told.