Since May 2015 Amazon has demanded you spend £20 on goods in order to qualify for free Super Saver Delivery, and that's a real pain when you're just a small amount short. Here's how to get free delivery on Amazon.

If you're buying books you need spend only £10 in order to qualify for free Super Saver Delivery on Amazon. For everything else the requirement is to have at least £20 worth of goods in your basket (£25 in the ROI), which is a real frustration when you've searched far and wide for the best deal on the web, yet the delivery charges push you to more than you wish to spend.

There are three ways around this:

1. Sign up for a 30-day free trial of Amazon Prime. You can cancel at any time, but during your trial you get several benefits including free next-day delivery. See What is Amazon Prime for more details, plus How to cancel Amazon Prime.

2. You borrow a friend's Amazon Prime account and have the item delivered to your address for free.

3. You fill up the basket to meet the requirement of £20.

The third option will be the option taken by the majority of people, we suspect, but there's no point wasting money on things you don't really want or need - unless doing so is cheaper than the cost of delivery.

Say you've spent £17.99 and delivery is £3.99, taking you to £21.98. You can save yourself £1.98 by adding an item that costs £2.01 to your basket. And if you do that, in effect you get that item for free.

So the next problem is finding an item that costs £2.01 or as close to £2.01 as you can. And this is where filler item finder services come in.

Best Amazon filler items: Get free delivery at Amazon with filler item finders

We like, which searches Amazon UK for items of a specific price. You can narrow down the search by category - such as Beauty - to help you find something you might actually want to use.

Browse to the website, then enter the amount you need to spend to fill your basket to £20. In our case that's £2.01.

Now choose a category from the drop-down menu. We've chosen Office products.

Amazon Filler Checker

Click Find It! to begin your search.

FillerChecker will search Amazon's entire UK store for items that are as close to that amount as possible, then return a list of results ordered by price from low to high. 

Amazon Filler Checker

We found a PaperJoy Inkjoy 700 pen for £2.08, which takes our total basket value to £20.07 and qualifies for free delivery. It's cheaper than what we'd pay for delivery, and who doesn't need a pen?

When you've found an item that you'd like to order, click on the link to be taken directly to its product page on Amazon and add it to your basket.

Read next: Know your consumer rights when shopping online.

Follow Marie Brewis on Twitter.