Ask HN: What gpu standalone box do you recommend for deep learning?

I'm currently looking to buy something to train deep learning models, as my laptop doesn't have a GPU. I'm looking for something that's not too expensive (max 400$)

The two main things I found were :

* The intel movidius stick : developer.movidius.com. Seems practical, as I can use it anywhere

* The Nvidia jetson : a bit like a raspberry pi but with a real gpu. It costs about 300$

What do you think of those two products? Would you recommend something else ? My use case is mainly to test new architectures and things that interest me, but not to train production models.