I am building the AM8 - Metal Frame for Anet A8 - https://www.thingiverse.com/thing:2263216
And paying ~£20 - £30 for a Y Carriage Plate wasn't high on my to do list.
Wasnt keen on 3D printng one, So I ended up drilling 2 lots of 3 holes in a bar of 2020, and tapping / bolting them together.
Combined with my LM10UU to 2020 STL,This works nicely.
It is surprisingly light - 2020 section is 0.4 kg/m and there is probably about 80cm here. - Probably not AS light as the 'Proper' solutions out there, But... Its rock solid.
Anyway - I uploaded this because I haven't seen anyone do it yet.