Are they Samsung OEM chargers or third party? If you list them they can be checked against reviews by experts.
You need three in addition to the one that comes with the phone? Keep in mind the Google ones at least come with cables so he price isn't quite that bad, there's some decent car chargers that are far cheaper too (like Nekteck's for $15 w/built in cable).
Yah upstairs, downstairs and in 2 cars, so ideally 4 chargers.