In case some is curious about how it is in Europe: I'm a PhD student (physics) in Denmark and I get 2500$/month after tax. I save from 1000$ to 1500$ each month. Disclaimer: I bike everywhere and share a 1400$/month flat with partner. Also, the entire pay comes directly from the university, I never had to apply to get funding after getting accepted (this was the main reason to go to Denmark).
Here in France: I had a ~1 900€ salary after taxes (incl. income tax, 2 000€ otherwise) but because I was working in a company fulltime (the contract stated I was to devote myself 100% to my research, the reality was different but that's another topic).
My partner, on the other hand, has a public contract (with teaching charge), she gets around 1 400€ after taxes. Living with this in Paris is not easy (1 studio of 15m² will cost around 650-700€)
