If I remember correctly, I had to put my reg in at the desk (the computer system had already read it on the way into the carpark! and I just confirmed it as mine) and then I had to get on my mobile and pay £20 by credit/debit card using some automated system. It wasn't just my mistake, the staff on the desk told me to do it and there were other people in the carpark on their mobiles doing the same thing.
Maybe that system has changed, but I have just checked the Travelodge website and if you hunt hard enough it says some Travelodge site parking is free and most Travelodge parking sites will incur a charge. It doesn't tell you the charges though.
Anschutz 2013 MEC1 .22LR
Miroku 3800 12bore