From my experience, you can buy/read Marvel and DC comics through the regular Comixology app--what Jim did with the coupon code means you have to read that through the specific Marvel app of Comixology. I've also definitely seen the Marvel Mondays sales on the regular Comixology app.
Comparing the price of comics with the price of games doesn't work quite well, because while five new Marvel comics would cost about 20 bucks, but a new video game nowadays is easily around 60 dollars. It has some comparison, because, like you said, the life of a game's a lot longer, and you can get older and used games for 20, but it's not an EXACT comparison, and from what I've read, a lot of companies are going to essentially penalize gamers for buying used with codes for important features, like the Catwoman segment in Arkham City.
Also, if you want to support digital comics as literal digital comics, 2000AD's recently started doing that. The only down-side is that they go by British pounds, so last week's issue is released for 1.99 pounds which converts to $3.21.
GL #7--I enjoyed it. Definitely can see that there's a bit of a pattern with the last arc, but the whole Hal/Sinestro/Carol relationship stuff is still very compelling.
I wouldn't have minded them tweaking Carol's costume, but it doesn't really bother me as much. I'm just glad that they confirmed she still has it--I'm pretty sure she's still considered Queen of Zameron, I wouldn't be surprised if Johns goes back to that after the whole Third Army shenanigans. Plus I like how it makes Carol different from Hal--he's irresponsible about his home life, and Carol is irresponsible about her semi-imposed superhero life.
GLC I enjoyed--it was definitely a filler thing, but I think it works really well.
I think I read Tomasi somewhere literally say that he's making GLC a cosmic war book.
New Guardians...the character of Invictis didn't really grab me, but the interaction between all these characters was cool.
Sayd being the one who brought the New Guardians together? That's an interesting idea.
Red Lanterns was cool--I like these new villains of Atrocitus' failed experiments. I honestly don't see the problem with the different plot points--this is really no different from stuff from the Bronze Age where every issue was semi stand-alone while still continuing a story with many different plots going on at the same time. This is basically a creepy, post-modern version of what Claremont did with X-Men.
"Why were they former Sinestro Corps people Bleez was killing?" Same reason why there are Tamerans and Maltus in New Guardians--to show that there's a shared universe.
How I would rate it this month:
GL
NG
RL
GLC
Good episode.