The Selmer 1430 or Kessler Custom seem quite a bit more affordable - obviously student horns, but perhaps enough for getting started.
Yes, I agree with tictactux. You (i.e. anyone) can sound great on almost any half decent bass clarinet (as opposed to those which are less than half decent, some are truely awful). The student models like Vito, (old) Bundy, new Conn-Selmer, student Yamaha 221, older student Yamaha 220 (Vito copy), Jupiter from the last few years and maybe others.
I agree with SOTSDO about the Chinese ones. Some like them, but I have tried many, both low Eb and low C, and I can't imagine any of the ones offered (e.g. Kessler) is significantly different from those I've tried. They all just had too many issues IMO. Though some of the student models are better than others e.g. I like Yamaha and Jupiter significantly more than Vito. The only advantage of some Chinese models is giving you a low C at a low price. I'd take a better instrument to low Eb than a poor one with low C.
I also agree about the the double register key (as opposed to just a seperate throat Bb key) being better. In general at least, since the worst bass clarinet I've ever played actually had the double reg key. They do allow better response and intonation that is a little difficult otherwise.
For example, see the attached example. This can be next to impossible to play legato (not tonguing the higher notes) at, let's say around 100+ BPM, on some of the student instruments. This is obviously not necessarily a reason to buy a pro Selmer or Buffet as a beginner, but it could be, or at least at some point. There are other reasons of course.
Instead of buying a new horn, I would see if I could purchase a well maintained used pro model. The low Eb horns don't usually cost that much used, and you don't really need a low C horn for 99.99999% of what you will encounter.
Yes, a used pro model can be a great option. Re the second part, it depends who is "you" and what you encounter. I use the extra low notes very often. I actually don't remember the last time I've played a concert without using any of them. Not that everyone else would, but it's up to every player to realize what they want to play.