If you're drinking in groups it's usual for one person to go to the serving counter to buy drinks for all the others, in rotation. If you're a skinflint you try to be the last in the list and hope your name doesn't come up. Paying for drinks individually is deemed bad sportsmanship. This can prove expensive if you drink a small number of small measures, in the company of big boozers. Real Ale is an acquire taste, but once acquired is rarely abandoned.
Microbreweries often brew something that's a cross between standard and real ale.
Most pubs are owned by brewing companies and won't sell other beers - perhaps a 'guest ale' like old scroat's but generally pub ownership is seen as a business like any other. A Free House, rarer, can sell what it likes. See our Nightlife Page for details and pub recommendations.