tis a slippery slope and no mistake!
no licence needed as such, but if you've never taken a boat to sea on your own, an RYA powerboat course might be worth while, or IMHO, better still, find someone with experience to come out with you a few times and show you the ropes. If you have a vhf on board (and you should) you need a licence for that, but amazingly, its one thing the government have now made free!
if its something that is trailable then no mooring fees to pay - 16 to 18 foot or so will set you back a grand a year in the marinas on the tyne or sunderland
there's slipways at sunderland and south shields, but theres an annual fee of 70 quid or so to pay to use them and you need insurance - depending on the boat and the insurance company that could be as much as a couple of hundred quid a year. Cullercoats beach is another option for launching. If its trailable, your options do open up much more in terms of being able to drag it around and about, to different places - couldn't imagine going up to scotland without a boat now
there's plenty of inexpensive boats out there to get you out and fishing, and if you can find someone to come along and have a look at potential vessels before you part with your hard earned, it would be a wise investment. Its all too easy to let your heart take over your wallet and buy something you shouldn't, then you get it home and realise how much extra your now going to throw at it!