if its twin cable I assume you only want 1 feed connected then they range from about £95 upto £200 +++
all depends on the spec, what you want, internal HDD support etc etc??
I bought a zgemma h3t2c recently and it does twin tuners for cable and works it very well too, only paid 92 pounds for it, has one satellite feed feed also, I was gonna go for the zgemma h52tc which is twin sat and twin cable but one of the feeds coming into the house the signal fluctuates so makes funny noises so dont use that feed, the plus sides to it is I can watch a cable channel upstairs on kodi on my android box upstairs too via the webif.
you have the option to choose a box with 2 x dvb-c = 2 tuners requiring 2 feeds or a loop through. Or 1 x twin setup only needs 1 feed connected as tuner splits internally. so you can record 1 watch another.