Got my mint condition iPhone 4 for $65, upgraded to most current iOS (7.1.2), used Pangu to jailbreak and install Cydia, installed Veency (VNC), now I can remote into the iPhone and don't have to carry it around. Note that if the iPhone is rebooted and not activated on a cellular network you will have to unlock before it connects to Wi-Fi.
I carry a Nexus 4 (Android) and I am generally anti-Apple, overpriced and pompous. I pay $7 to Vanguard for a trade and only trade at least $1k at a time to justify the trade cost. I could justify a Apple device since it will pay for itself in 7 trades and I can trade lesser amounts. I would use Interactive Brokers but not willing to tie up $10k.