To jump in with Keith on the self build here, there is not a lot to it if you can handle a few tools.
The body/neck can be as simple as a plank. "Wings" can be glued to the sides at the tail end if you prefer some shaping but don't have a band saw.
The bridge/tailpiece is a piece of angle ali, brass or steel and the nut - the same.
You can buy 8string pickups or, like Keith's picture, two P-bass units. I made a 7string steel guitar using a cheap jazz bass copy p/up that is wide enough. 7 or 8 strings is my recommendation but 6 is useful, it's just that the extra one or two give scope for more tunings.
Check around music shops or instrument makers for "odds and ends" boxes to find tuners in singles or other than sets of 6; maybe left over from repair jobs. At a pinch a mandolin set could maybe do if robust enough.
Fretboard can be as simple as cardboard marked off from a regular guitar as a template. You make the scale length of yours to match the distance from the bridge to one of the lower frets; around 22 - 24in would be good enough. F'rinstance, from the first fret to the bridge of a Les Paul looks ok. Or, Keith has a contact for reasonable complete fretboards with dazzling inlay designs (is that one of them on the blue job?)
You don't even need volume and tone controls, wire up straight to a jack socket. Pedal steel guitars don't have them, although a vol. pedal is used.
The point here is that you CAN make a reasonable guitar for very little money before you plunge in and spend on either a good instrument or better materials to make your second one.
Ask if you want any help or advice.

PS let the available parts guide the design!