The GT 730, which launched in 2014, was priced at $70 to $80 when it came out. But at the moment, brand new GT 730 graphics cards go for around $50, while you can find used examples at around $20.

Here's a comparison of the GeForce GT 710 against Intel's HD 500 ... like the Radeon R7 240 / 250, or the GT 730/740, that were already doing a far better job than what the GT 710 was offering ...

This builds a CUDA-enabled Tensorflow for the Nvidia GeForce GT 730 (CUDA 3.5), but should serve as inspiration for other legacy GPUs. I use it on my HP Proliant N40L, which uses a AMD Turion(tm) II ...