That's a nice looking bass.
It's Oriental, my guess would be early 80s Korean, but might be late 70s Japanese - although my gut feeling says not. I'd like to see closer pictures of the bridge - is it brass/does it have brass saddles? Is anything stamped on the neckplate?
The headstock is very similar to early 80s Hondo Precision & Jazz copies (which I think were built by Samick in Korea), although these usually have full-size tuners. The tuners featured here can be found on millions of Japanese basses of all brands, from the early 70s onwards, and also appear on Korean-made basses too. Can't be sure but I doubt the control knobs are original.
The styling definitely says around 1980 to me - the mahogany (or stained to resemble it) body, maple board & cream pup, chunky bridge & non-Fender headstock. This was the era when the leading Japanese brands were moving towards original designs, but still very based on their copies - and like Ibanez's Blazer bass of that era, this is basically a re-styled Precision.
I've seen a few late-ish D'Agostino guitars, and these were rebranded Corts, from the early 80s. Construction was neck-through, with that Alembic/Matsumoku stripy styling popular in the early 80s (before everything went pointy!) and brass hardware, including large brass truss covers & 3-dot fretboard inlays. These were also sold as Targa, and lots of unbranded ones were sold in the UK.
Anyway, like most Oriental instruments of its era, this bass resides in a pretty much fact-free zone! I've typed my observations about the bass before reading the other posts on the thread - and it's interesting to see how different assessments can be. I wouldn't have considered it to be anything other than Oriental, for example, because of the hardware, and the styling dates it at early 80s, or even late 70s - which is completely inconsistent with Vintaxe's info about D'Agostino's production sources.
I'll just echo what Cheepaxes says about rebranding. My field of interest is mostly 70s Japanese - the copy era specifically - and it's fascinating to see how many different brands all seemed to come from 3 or 4 factories. Even the best-known names, like Ibanez or Aria, did not have their own production facilities, they simply contracted factories to build to their specifications. In the UK, Ibanez sold alongside a cheaper brand called Antoria - many of which were exactly the same instruments, even down to the model numbers.
Anyway CWhitten - not a piece of junk in my opinion, I think it looks great (I'm a sucker for the maple board/mahogany body look!) and if it plays well & sounds good - then that's your answer. As far as value's concerned - these things are really only worth what someone will pay. Me - I like cheap & unusual basses & guitars, which is why I have a ridiculously large & ever-growing collecton of JapCrap firewood (irony!) which has cost me less than many people will happily pay for just one bass.
There's a moral there somewhere, but I'm not quite sure what it is.
Jon.