You may have purchased a classic at the Goodwill.
Then again, maybe not. This quote from the Farfisa wiki page:
"
The Farfisa brand name, meanwhile, continues to appear on contemporary MIDI keyboards."
Which in the context of this particular thread makes one suspect he may have got one of those rather than one of the 'classic' (which were all without midi, for one thing).
Would be interesting if OP would reveal precise name of said 'cheap' thing he actually bought.