2 external displays on your macbook pro 2015 I'm just asking again. It has been asked before, but most answers are quite old, so let's give it another try. 

I've just bought a new Macbook Pro 15 inch 2.2 Ghz, a 2015 model of course. Now I want to connect two external displays using thunderbolt only. I don't want any difference in quality whatsoever, so one thunderbolt and one hdmi doesn't seem a good option to me. Even my dad has a laptop which allows him to connect multiple screens, an external keyboard, ethernet and has plenty of usb ports, so why shouldn't this be possible with a much more expensive macbook pro? I can't find the answer on the internet.

So far it seems it's only possible to buy two thunderbolt displays, which is really too expensive, but has the possibility to connect multiple usb devices, display, and ethernet using just one thunderbolt port.

There must be a way to connect two dell displays to the macbook pro and ethernet (possible the keyboard as well), using only the two thunderbolts, is there?
The Thunderbolt ports can be used as regular miniDisplayPorts. Modern Dell screens have DisplayPort or miniDisplayPorts. The only difference to HDMI is that DP supports higher resolutions.