Low budget machines could lead only to frustration, i believe.

The Alu profiles are expensive for a build.

For me the cheapest CNC should have the following things as a must and then around them build the rest:

-water cooled spindle and VFD.
-reliable breakout board
-reliable motor drivers
-supported rails

Save some more money and buy a mini mill, at least you will definitely return your money producing some quality things.

All these 3040 and so are toys.

Sad but true.