Most clubs/parties I know are bring your own booze Ronin. for cheap bondage get a packet of cable ties or some scarves. to see if there are any clubs near you look up munches on the net. its a good way of meeting others over a drink/meal.
Well, That depends on the event.
Obviously for a home party - Like an tupperware party with leather and rubber cocks - You're most likely going to have to bring your own booze, if it's a drinking sort of thing.
For Munches, most commonly, they're held in bars, pubs, or the like, and you can most likely buy booze on site, but sometimes it's held in non-booze venues - I've seen them held in churches before, which was always a laugh - but most likely, it's a pub, front up the bar, grab your grog and go.
For Larger events, Such as the Skin Two Ball(first example that popped into my head, but I wouldn't recommend them except recommending to avoid them, they're elitist CUNTS and that sort of thing on the scene needs to die in a fucking fire) they generally have a bar of some sort set up, because it's a fantastic money spinner for the event. Drinks will vary in price, but they'll be there, 99% of the time.