Budget Cellphone

In need of a new phone. My iPhone 6's battery is nearly useless.
Phones are pretty expensive, especially in Canada and as a student I don't have much money to spare. What phones would you recommend for say $500 budget?

You can purchase an iPhone 6s for around $130 (eBay) or $200 basically new all over the internet. Otherwise your options are pretty limited to old versions of iPhone and plenty of android phones.

You could also just pay to have your battery replaced, it'll be much cheaper than a new phone.

Samsung s6, had it for almost 4 years works like a charm, still fast, and is illy cheap