So, you're looking secondhand? -
eBay? If your patience t and can wait a little then bargains are about..
As for good and bad "brands" most bikes that were say £300+ new should be of reasonable build quality and reliable if they've been looked after.. Try asking in here about specific bikes if you see some you're interested in..
There's many good brands that are good, it's down to taste and personal opinion, you need to know roughly what size bike you need as buying one we the wrong g size will be a pain (literally when you start doing longer rides) I assume by hybrid that you'll pretty much be riding on tarmac but want flat bars?
Some good brands/model lines:-
Giant
Trek
Dawes (discovery range)
Specialized (sirruss very popular)
Aah too many....
Considered bad and to avoid:-
Apollo
Ammaco
I'm sure others will add more, carrera bikes aren't bad at their specific price points...