I'm going to go counter to some of the advice here and say that the guitar cab will probably be fine, so long as you keep the volume under control and the wattages line up.

Having said that, as a studio owner and longtime soundman who gets to work with tons of bass rigs, here is my 2 cents on bass rigs:

• for most bass sounds, the cab matters as much or more than the amp. This is inverse of guitar. With bass, the speaker is (usually) where the most important limitations happen.

• wattage and headroom are in a constant battle with weight and cost, when it comes to bass. Even if you favor a super-distorted, lemmy-style guitar sound, you just can't get that bottom-octave size and punch to compete with a drummer, unless you have some serious power-handling.

• Buy used, and buy brand name, especially early in your journey. Is an Ampeg pf500 way better than a Behringer class D amp of similar wattage? I have no idea, but I do know that it will be way easier to get your money back from craigslist if your amp says Ampeg, GK, Eden, Genz Benz, Markbass, or even Hartke or the right model of Peavey, than if it's some no-name or off-brand.

That above consideration is huge. If you buy used brand-name stuff, and shop smart, you can almost always re-sell it for about what you paid for it. But if you buy the cheapo deal of the week from guitar depot, it loses half its value the day you take it out of the store.

I think the best deals on guitar amps are usually combos, but the best deals in bass amps are usually separate heads and cabs. Most especially, there are some fantastic class-d bass heads with huge sound and high power, that are very affordable if you shop smart, these days. And you can pretty much always pick up some kind of old beater 4x10 on craigslist for inside $150.

That approach will allow you to gradually save up another $150, and upgrade your cab to something better, when you (easily) sell the old one for what you paid.

Have fun!