The very first brand new bass I ever bought was a sunburst shortscale 'Top Twenty' from Woolworths for £27.00! The single pup was (unsurprisingly) so rubbish that I ripped it out and replaced it with a cheap six-string guitar pup I had lying around. Believe it or not, I actually gigged with this bass for over a year with no adverse comment!
My actual first bass was custom-built (by me) Brian May-style from a rectangular lump of old mahogany fire surround, to which I attached the neck purloined from a neighbour's Spanish guitar. The m/heads were 4 substantial nails, to which I attached my own branded hybrid flatwound/roundwound strings - i.e 4 lengths of bright green heavy gauge wool nicked from Mum's knitting basket! Needless to say, the action was a bit high and flabby, and the overall sound was not as similar to a Ricky as I would have hoped. But it was a start!