3 Amazon Mistakes I've Made That Cost Me Big-Time

Here's how to avoid falling into a similar trap.

One of my favorite things about shopping on Amazon is that it allows me to procure the items I need without having to leave the house. Plus, Amazon does tend to offer competitive prices on much of its stock, so shopping there often means enjoying some savings.

But as much as I consider myself a bit of an Amazon pro, I have made my share of mistakes when using the site. Here are three in particular that wound up costing me money.

1. Not canceling a subscription I no longer needed

One of my favorite Amazon features is its Subscribe & Save program. With Subscribe & Save, you set up deliveries of the items you use regularly so they arrive automatically on a preset schedule you determine. Often, you'll get a discount on those items, too.

When my twins were born a little over seven years ago, the Subscribe & Save program helped us save a fair amount of money on diapers. We had multiple cases delivered on a monthly basis for several years.

When my twins were 2 years old, they became potty-trained and our need for diapers thankfully went away. But that month, I forgot to review my Subscribe & Save deliveries, and so several weeks after hitting that milestone, I received a massive order of diapers I didn't need.

Since I couldn't return them, I wound up giving them away. And while I suppose I can take comfort in having helped another parent who needed diapers, I was annoyed that I'd spent the money needlessly.

The lesson? If you're going to use Subscribe & Save, review your purchases every month. You may no longer need a given item, or you may have enough of a stockpile that it's worth skipping a delivery and not having that extra charge on your credit card.

2. Ordering a free try-on and forgetting to send the item back in time

As an Amazon Prime member, I'm entitled to the Try Before You Buy program. With Try Before You Buy, you can have apparel delivered to your door without being charged anything. You then get a week to decide if you want to keep the items in question or return them at no cost.

Last year, I ordered pants for my son that wound up being too small. Only I got busy and neglected to return them by the end of our one-week try-on period. The result? I'm stuck with an item I can't use. Because the pants were inexpensive, I wound up gifting them to a friend with a younger son, but it was a silly mistake on my part.

Going forward, if I use the Try Before You Buy program, I'll be sure to set up a calendar reminder for the end of my try-on period. That way, I'll be more likely to remember to send things back when needed.

3. Assuming Amazon had the best price on a holiday item for my kids

Amazon tends to have great prices. This past November, I noticed that a board game I wanted to buy that normally retails for about $35 was on sale for $27. I scooped it up in a hurry because it was a gift I'd already had my eye on.

No sooner did that item arrive at my door than I happened to stumble upon a competing retailer's website who had that same item available for $22. Now obviously $5 isn't a life-changing sum, and ultimately, it didn't really impact my holiday budget. But it was still annoying to have spent $5 extra.

The takeaway? Don't assume Amazon always has the best prices. Instead, spend a few minutes looking around before finalizing purchases.

For the most part, being an Amazon customer has saved me money through the years. But I'm sharing these mistakes with the hope that others will learn from them -- and, ideally, avoid falling into the same trap.