Help me find the fastest phone new for under $300 gsm or cdma

Hey all. After about 8 month with the ZTE Boost Max (Iconic) I'm ready for something faster. Dual Core, 1 GB ram just isn't doing for me at all. I'm currently on Boost and my service here is horrible. I moved 2 weeks after buying this phone and was just gonna wait it out til now. So I'm looking for something 0 or less new. Maybe the Zenfone 2 seems to be a beast especially at 9 to 9. I've looked at some new options from ZTE but seem priced pretty high. I prefer a 6 inch phone but no less than 5.5. I'm on a 5.6 inch phone now. So don't really wanna go smaller but bigger is a possibility. I thought the MX4 was cheaper but it seems pricey like flagship phones. I've been out of the phone world the last 4 or 5 months due to a new 50inch tv, ps4, new dell laptop :)

I've been doing research in google but so many threads refer to the flagship phones and aren't really talking much in terms of price or budget.

Thanks
Josh