The battery on my laptop finally got to the end of its life, so I had a look around on the internet for a replacement. A genuine one had a price of over $200. Yikes! The battery specialist in a bricks & mortar shop a couple of suburbs away had one for $110 or thereabouts. Then of course the various internet sites had offers ranging in price from a little over $50 upwards.
I've often booked air tickets and accommodation over the internet, and at one time bought some books from Amazon. However, I haven't had a lot of dealings with what you might call "run of the mill" selling sites (although, from what you read, lots of people do buy things on the internet all the time). I was a bit concerned that a couple of the sites that I came across seemed a little short on contact details. One or 2 had 1300 phone numbers, but one had nothing apart from an email address (so I dismissed it immediately).
As it happened, one of the cheapest offerings came from a site that set out a street address in a Melbourne suburb, a landline local phone number, the name of the company behind the site and an ABN. I know that none of these can be absolutely relied on as providing evidence of good faith, and I would have been more reassured had it been possible to pick the item up at the street address (which the site said was not possible - presumably the items themselves come from various "interesting" locations!) However, I trusted them with my credit card details, and I'm gratified that the battery duly turned up a couple of days later. Not quite the "next day" service mentioned, but I'm not complaining and a lot more convenient than trudging across town in the pre-Christmas traffic. And at least so far there haven't been any unusual transactions on my credit card account.