Don't trust the first prices you see on Google Ads or sketchy sites with weird names - there's a lot of scammers selling refurbished phones while claiming they're new, or they hype up the "condition" rating way beyond what the phone actually looks like. What people often forget is that a phone in "good condition" from one seller might have huge scratches on the screen while "fair condition" could mean almost like new according to someone else. Always read the specific criteria and photos on each site before you start comparing prices.
Big marketplaces like Back Market or Swappa are definitely safer because they have easy returns and sellers rated by users - but you still need to filter smartly. Look for sellers with tons of positive reviews (99% or higher), and take the time to read the negative comments to see if there's a pattern. Deals change constantly, so compare across those platforms but also check directly with phone carriers or big electronics chains - sometimes they do nice discounts on refurbished phones sold through their own services.
One thing people easily miss: check the battery. A phone can look absolutely perfect but with a battery degraded to 75%, it's a pain to use day-to-day. Always ask for the battery health percentage before buying, and skip any deals that hide it. Honestly, paying 20-30% less than new while getting 18 months of warranty is already pretty fair.