I'm afraid your friend was misinformed. There are many ways to pay the charge. You can pay up to 90 days in advance. So, for example, you could pay for one day, three days, a week, two weeks, a month or a year. If you pay monthly or annually there are discounts available, and you can claim refunds in certain circumstances.
You can pay by midnight on the day of travel (£8) or by midnight the following charging day (£10) by phoning them and paying by card.
You can also pay by SMS, at a shop, at one of their machines in the street or in advance by post.
As for the train, I use it to go to London on business and if you travel in peak times (arrive in London before 9:30am and leave London after 3pm) then Virgin trains charge £225 return which makes me angry to even type it. It's pure profiteering and, of course, is passed on to my employers customers. A fine example of rip-off Britain.