Show me a $70 smartphone that can run for months on a single charge, looks fine without a backlight, and has instant response time, and I'll use it to replace m

Show me a $70 smartphone that can run for months on a single charge, looks fine without a backlight, and has instant response time, and I'll use it to replace my TI-83. Maybe. I'm not sure I want my calculator showing an alert about what my friends are doing tonight when I'm trying to focus.