Well, there are a few ways around that if you have a little patience and you're willing to bargain hunt...
Wait one month or so for the price to drop -- Most publishers will drop the price of new releases after one month. DC Comics, for example, drops the price of their $2.99 books down to $1.99 and their $3.99 books down to $2.99. IDW, meanwhile, will drop their $3.99 books down to $1.99 after the first month, which is an even better deal. Unfortunately, the main exception here is Marvel, who seems frustratingly locked into the notion that new $3.99 titles such as Avenging Spider-Man and Uncanny X-Men need to remain at $3.99 even after five months or longer. Granted, this helps brick-and-mortar comic shops stay competitive, but doesn't exactly make Marvel competitive with other publishers on the digital front. You could be doing a lot better with this, Marvel.
Look for the free comics -- Sadly, free digital comics aren't as prevalent as they used to be on iPad apps, but there was a time (okay, just last year) when all the major publishers were posting free digital comics for you to enjoy on their respective apps and ComiXology on a consistent, weekly basis. Well, the last free comic DC posted was End of Nations #0 on November 18, 2011 (three months ago to the day) and it's just been "Sneak Peek" promotional previews ever since. Dark Horse currently has 33 free comics available, but it seems like 85% of them have been there for over two months or longer, so there's a serious staleness factor there. Surprisingly, the big winner for free comics is Marvel, who regularly posts two or three new free comics every Tuesday night. Some of the offerings are even as recent as last summer, others from ten years ago or older, some are top books, others obscure gems, you name it. Yeah, they also throw in some promotional stuff, but some of it can be exclusive prologue stories to upcoming events like the Avengers movie. Other publishers should really follow Marvel's lead on this particular front.
Wait for special sales -- This is the big one for bargain hunters. Every week or so, ComiXology and/or a certain publisher will offer a weekend or holiday discount sale focusing on a particular character, team, title or theme. Most of these discounts offer titles for just $0.99, the price most of us are willing to pay for comics we already own and love again in this newer digital format. DC Comics has been embracing these sale promotions more and more with things like their excellent "101 Sales" that offer 101 classic and recent titles of Superman, Batman, The Flash, whatever the theme is that month, for just $0.99 each. Marvel is right behind as well, but they choose to concentrate on Mondays and Fridays for their $0.99 sales. Dark Horse and IDW will have a similar sale every so often, as will Image and Dynamite, but nowhere near the frequency or scale as DC or Marvel. Regardless of the publisher, though, these special sales are great ways to build a considerable digital comics collection and get runs of titles like JLA or Astonishing X-Men for far less than you spent buying them in paper.
So all in all, the bargains are there if you keep looking for them on a regular basis and aren't focused solely on just a few specific titles. They're also a good excuse to try something new, as I did with Image's Morning Glories or IDW's Star Trek ongoing series, so go ahead and see what's out there. You might like what you find.