If you're on a budget and want an Android phone, you usually have two choices - buy one of the many low-end Android devices, or purchase an old flagship. For the latter case, you can now get a manufacturer-refurbished LG G4 for just $119.99 - about $130 less than the unlocked G4 on Amazon.
Now before you jump to buy it, there are a few things you should know. Although these devices are manufacturer-refurbished, they do not include a warranty or the original packaging. In addition, the seller states that the devices are in "8 out of 10 condition," with small imperfections like scratches to be expected. Finally, this is the AT&T variant of the G4 (H810), and there do not appear to be any custom ROMs available.
Still, if you're willing to accept those compromises, you can grab it from the link below. It's worth noting that this device can be updated to Android Marshmallow.