I bought an unlocked 2nd hand Galaxy S5 from cash converters for $180 in as new condition.
I like the S5 because it's waterproof and has a replaceable battery. The batteries do wear out after a year or so. A common complaint from high end phone consumers is that after a couple of years it's no longer holding charge .... so they need to upgrade to another $1500 phone
You can actually get rebuild kits from ebay for around $50 with a replacement battery and the special tools required to dismantle the phone, often it involves heating the phone up gently to unstick the glue which holds it together and then prying it apart with thin pick tools. It can be done, if you're determined. My mother has replaced the battery in her iphone 3 times.