to use a cheap ebay 3.5" TFT (http://ebay.eu/2jn9nHO) on a Pi0?
From the looks of the install instructions on that page; yes. But I’d expect it to be a struggle to get up and running, and to receive all the technical support I paid for… ie: none :D
There’s a chance, as it’s an SPI display, that it will just work with FB TFT, but since they don’t list which controller chip it uses, it’ll be tricky to find the right one- although I suppose you can ask first! Compatibility table here: https://github.com/notro/fbtft/wiki/LCD-Modules
Avoid pre-made SD card images shipped from display sellers, they’ll likely be hideously out of date, may not work with the Pi0 at all and will explode if you try to update them since the updated kernel will mismatch with the pre-installed display drivers.
A safer bet, if you need to save money is to go for an HDMI one like this, and use a dongle to make the mini (or is it micro? I forget) HDMI connection on the zero fit the adapter.
I am waiting for the 5" one archieroques has linked to, to arrive. will post mt experiences when it arrives.