Hi, I know this is a generic question, but so far I have these in mind when I'm buying a bass:
1. Price (of course

2. Tone
3. Neck dive
4. Action
5 .Weight
6. Neck
What am I missing?
best regards
Price is definitely important.
Comfort (weight, neck size, balance, ergonomics): some basses just don't fit well when strapped. Neck dive can be somewhat fixed depending on your technique and strap. Bass has got to feel good playing and not cause unnecessary fatigue (although that could be due to technique).
Set-Up (action, intonation, tone): I include tone because a full set-up, to me, includes changing pickup height which can change your tone a bit. There's a good chance the action is too high or low, but if you're already considering getting new strings (add to the Price), you really want to consider a good set-up (also add to the Price unless you're good at it yourself or know someone that can do it).
Electronics: someone already mentioned Passive vs. Active, but don't forget to plug in your potential new bass and turn all the knobs, flip the switches (if it has any) just to make sure
everything works (no scratchy pots, no useless switches). Find out if the pickups hum too much or microphonic by tapping them (
my budget bass has very microphonic pickups unfortuately). Figure out all the
tones your bass can do to assess what new strings or any modifications you may or may not want to buy.
Other things: you may want to reserve some money for new strings, a good strap, perhaps some picks, definitely a good cable to connect to a potential new amp (which I'm sure the Amp Sub-Forum has lots of recommendations). Eventually, you may want to wade into the deep pool of effects, but that's yet another Sub-Forum.
I'm also going to include
Looks. Gotta look good.