Come on guys. back in the mid-80's when an Alpine Cassette head unit was king, they were running around NZD750 before you added a graphic and an amp or two. A Nakamichi was more like a grand or $1200 - and god did they sound good.
Here's a 7273 from 1985 - if you had this, some amps and decent speakers you were - worried every time you parked your car! (stolen without permission - tried to link. Thanks to http://magnitola.org/attachments/golovnye-ustroistva/1272233d1553761180-Magnitola-Avtozvuk-img_0086.jpg
... And in '89/90 and a good CD deck was a grand - yes A Thousand Dollars with an amp, installed... and it skipped on bumps on the way to the mountain, needed an external amp just like yer Nak tape deck did.
The TD1200 - OMG.
$900 for a Blaupunkt in today's dollars? Not a lot, really. The phone in your pocket is probably worth more than two grand.
Then there's the KMM-BT408. The Kenwood mechless decks actually sounds good if you feed em WAV files. Cost buttons, really, to boot.
Just a thought @deedub - those guys doing bluetooth conversions on old gear probably charge more than you're expecting because they need to make sure it works for you for a good while.