I bought one on EBAY today for 54.95. 3/8" with a return line is the way to go. I use them for fuel injection and drill out the 1/4" return line and install a 5/16 line instead. The 5/16 sending unit was 2 dollars cheaper.
The turn signal part wont fix your turn signals if it isn't the switch. Usually bad turn signals, if it's the switch, often leads back to the emergency flasher portion of the turn signal switch.
Rob