A lot of us bass players mix and match, picking up heads and cabs here and there.
Other than combos, I can go with my SWR Workingman 4004 head, purchased for around $200 on eBay, with either an Avatar B112 Neo ($240 new) or a Flite 2-12 cab with JBL E140s. Or an old Peavey cabinet with a single 15, or, for tiny venues, a SWR Workingman 1-10 cab.
My point is that you don't have to spend a lot of money if you're patient and know what you're doing.