> Does anyone know how to cheaply and easly make
> your own water distiller>
There are many ways to make your own water distiller.
However, the biggest expense is not the device,
but the (usually electric) power it requires, because all that water has to be heated up, and kept at its boiling point for many hours.
> or is there a cheaper alternative ?
Store-bought distilled water tends to be cheaper
than the one that your distiller makes.
Rain water is the cheapest distilled water.
However, often times it's no longer potable.