What I do is this:
Say I want some 24.99 games...so I pick out 3 24.99 games since the best value is to get games that are the same price...
24.99 x 2 (since 1 is free) - 10% edge = $44.98 + 6.5% tax =
$47.91 with B2G1
...now divide that by the 3 games and EACH game would in essence cost you:
$15.97 with tax 'Average' PER GAME (ie. although it may seem that 1 is free, when you average it out its 15.97 a game)
Now, say you are not willing to wait and want to use a
20% coupon + 10% edge on those same 3 games:
24.99 x 3 -10% - 20% = $52.48 + 6.5% tax =
$55.89 with 30% off (10% edge and 20% coupon)...now divide that by the 3 games and EACH game comes out to:
$18.63 with tax PER GAME
Now say you wait for a
25% off coupon + 10% Edge:
24.99 x 3 -10% - 25% = $48.73 + 6.5% tax =
$51.90 with 35% off (10% edge and 20% coupon)...now divide that by the 3 games and EACH game comes out to:
$17.30 with tax PER GAME
In the end, as long as the 3 games you choose are the same price then B2G1 is an awesome deal...not by much but every little bit helps to a CAG.
Now, for a look at what happens should you choose NOT to get 3 at the same price...well that changes things because for example...
Say you want a 54.99 + 24.99 + 17.99...in that case the breakdown doesnt really work in your favor with the b2g1 as the average per game at that point comes out to:
54.99 + 24.99 + Free (17.99) - 10% edge = $71.98 + 6.5% tax = 76.66
divide by 3 =
$25.55 average PER GAME
So in this scenerio your actually paying MORE for the 17.99 game (& slightly more for the 24.99 game). Granted you ARE getting the 54.99 game at pretty much 1/2 off its current used price if it makes you feel better to look at it that way.
So you need to kind of look at that and say...OK can I get the cheaper games on sale later with a coupon and try and match up pairs of 54.99 games NOW?
OK I am tired of calculations Im out
EDIT: You can also look at the last breakdown and ask yourself, if you want some cheap games, can you just match all the cheapos together (17.99+17.99+17.99) and the expensive ones together (54.99+54.99+54.99) so that you can get the best benefit out of the deal.