Need help pricing a 70's Jazz Bass
 

Very lightweight with a slim neck
Plays great; never had it apart; looks to be all original.
What's something like this worth?

You're gonna have to take it apart (or have someone else do it) to determine if it really is all original. There is a BIG difference in value for an all-original vs a parts bass. That will also help you determine exactly which year it was built. It appears to be in very good but not perfect condition. Check ebay & the TB ads for an idea of the going prices.

I could be a wise guy and tell you it's only worth $200 and you should sell it to me, but I won't.

Yeah most buyers in the know are going to ask to see a neck stamp, and probably some pics of the pots and pickups to verify the age.

So assuming it's legit, what is the value?

$2600-3200 IMO assuming the finish is 100% original

$2600 being the highest you will sell it for. Thats about what selling... Anything higher than that and it probably won't be flying off the shelves.

Depends what part of the 70's this bass was made. A '71 will be worth more than a '79.

Early 70's. Look at the Pickguard.