When I bought my replacement charger from eBay, I found an eBay Powerseller with great feedback who had multiple recent feedback from satisfied eBay users who purchased the same charger. If you are buying a new or used charger from eBay or Amazon, I highly suggest verifying the seller has positive feedback and lots of it. Sometimes you'll see complaints and poor reviews simply due to a customer's own wrongdoing or lack of knowledge (IE they bought the wrong model) so you should verify the complaints are legitimate before judging too harshly. If you're worried about a low rating, I suggest checking out the reviews in more detail and seeing which factors customers complained the most about. Apple MagSafe 2 85W Power Adapter (MD506LL/A) for MacBook Pro. 45W Genuine MagSafe2 A1436 Charger Power Adapter for Apple MacBook.
In addition, the magnetic DC helps guide the plug into the system for a quick and secure connection. Apple 67W USB-C Power Adapter for MacBook Series - White. It also helps prevent fraying or weakening of the cables over time. I'd feel confident buying this MacBook charger based on the high number of positive reviews The 85W MagSafe 2 Power Adapter features a magnetic DC connector so if someone should trip over it, the cord disconnects harmlessly and your MacBook Pro stays put safely.