The Sky box and dish that you have are now owned by you (deliberate so they can charge you if you call them out for repairs to YOUR equipment, not theirs!), so cancelling will deactivate your viewing card, but you can still get loads of channels free without a card (including a couple of Sky's own ones), depending on what you like to watch.
Alternatively, there's FreeSat from Sky, which uses the same equipment and keeps you 'legitimately' in their ecosystem and gives you quite a few more channels than plain old FreeSat. You have to buy a one-off card for about £5 and then I think it has to be renewed every few years for another fiver. As you'd probably expect, though, they will use it as an 'in' to market 'actual' Sky to you quite a lot as an 'upgrade'.
We have the basic Sky package, now gone up to £24 a month. We grin and bear it and keep wondering whether to stop it after our contract is up, as 90% or more of our viewing is just on the free channels - but it's the extra 5-10% that we don't know if we want to do without.
Alternately, depending on what you like to watch, BritBox might be worth a look - £6 a month (rolls over monthly but no contract - first month 'trial' is free) and there's a lot of old archive stuff from BBC, ITV, C4 & C5. There isn't a colossal amount of stuff on there yet, but I think they're adding to it all the time.