In situations like this, I like to compare the price to fun ratio of games to beer.
Say for instance, "Indie Game 2286" is on sale at £1.25. Am I going to have more fun with this than the equivalent value of beer? Well that's about half a pint for me and me only, so if I get more than 10 minutes of entertainment out of it, then money well spent.
£45 is different. That's four or five crates of beer. That could fuel a small house party. Now that could very well be a highly entertaining evening. OR that £45 could buy me Rome 2, which given my history with the Total War series could amount to 200+ hours clocked before Christmas.
Guess where my money's going.