Don't, and I really mean don't, buy a bed base with thin wooden slats on canvas tape holding up the mattress. They're cheap, but they don't last long at all, and are hard to move around or transport. I would seriously consider getting a solid timber koala base or similar, then your choice of mattress on top if you don't like the koala ones. Sleeping Duck also do a good one called SD Indestruct. A mattress with handles on the side to make it easy to rotate/flip over is also on my essential list as rotating the mattress regularly extends its life well past the usual 10 year guarantee.
My own current bed base is a wrought iron art deco headboard and footpiece, with slot in steel removeable beams holding them together and solid wooden slats in panels that fit between the beams. I've had to replace one panel, which was fairly easy even with my primitive woodworking skills. The base is fairly high - high enough to fit a milk crate underneath it easily, so underbed storage is very convenient. I've had it 25 years plus and it has come with me through several moves and is just as good as new. The legs are integral to the headboard and footpiece - no separate screw in legs which are another point of failure in cheap bed bases. I've lost count of the bed bases that show up in the hard rubbish in my street that have clearly lost one or more screw in legs and are now useless.
In short, spend money on the bed base, and the mattress. Bed linen is often on sale, and you can change that around fairly easily, but a good bed base goes with you wherever and should last nearly a lifetime. Worth considering one that can be disassembled and re-assembled fairly easily too.
Snooze just do saturation advertising. I would also avoid Fantastic furniture - cheap shit and overpriced even at that price point. I did look into them a while ago when looking for a king single for one of my sons, but was seriously underwhelmed.
EDIT: if you have a cat (and you do) then I would avoid a box spring mattress. My parents' cat ripped a hole in the cloth covering the underside of theirs, and used to hide inside among the springs. Until someone sat down on the bed heavily .... there was this almightly screech and the cat ran out screaming. She had a kink in her tail for the rest of her life. I just shudder to think - what if it wasn't her tail that got caught?