I personally wouldn't spend more than about £350 on a bass. Neither my level of playing nor frequency of gigging would warrant it. There are some perfectly good bases around for that money, and anything over that is just a cascade of diminishing returns (i.e ten times the price wouldn't get you ten times the bass) I also just wouldn't feel comfortable taking a really expensive instrument to gigs. I've never understood the logic of people who have a 3 grand bass in the house and a £150 Harley Benton for gigs. Just give me the Harley Benton in the first place and I'm happy.
Now amps / cabs on the other hand I'd be willing to put a little more into. But that's only because a good power to weight ratio doesn't come cheap. If my back wasn't so knackered I'd happily pick up and gig one of the cheap Trace rigs that come up fairly often and go for peanuts.