A fiver, including delivery and any fees? I used to do what you say but ebay fees have become a rip off and game prices drop so fast now that even on the members market you are lucky to lose only a fiver including delivery.
I personally use lovefilm and have off and on for 3 years. From about 2 years total membership 2 games at home at a time I've only had to pay for about 5 months using 90 day trials over and over and 3 months for the price of 1 return deals.
Nothing beats free
I must have had 60+ games from lovefilm excluding the hundreds of dvd's in that time and it's no way near 50p a game total cost to me.
I like lovefilm they nearly always send me the latest game if I force the issue by having two lists and one list with one game in it.