FPGA on which it is worthwhile to do deep learning costs more than the iPhone, and consumes a lot more power. Your best option starting next year will be sub-$1

FPGA on which it is worthwhile to do deep learning costs more than the iPhone, and consumes a lot more power. Your best option starting next year will be sub-$100 Chinese chips with a TPU-like unit built in. The only one I know of is RK3399Pro, which was supposed to come out this year, but didn't make it, apparently because the die had to be larger than they planned.