I'm a little confused by your question. Your subject contained the question "Is making a photo album a good way to keep a loved on'es memory alive?" But your spent the whole text of your explanation talking about how expensive it is to get photos printed...was that another question, or was it your main question?
The answer to the first question is that it always helps with the grieving process to honor the memories of a person, their life, etc., in any way you can. That could be anything though from creating a photo album, to making an object of some kind, to creating a charity event/etc in her name.
Also, a "photo album" doesn't have to be only photos, especially where memories are concerned. You could use all kinds of things (from drawings, magazines, etc) that represent her interests, life, etc, and your feelings for her, rather than *all* of the photos.
As for the cost of photos, I'm guessing (because you didn't really say) that you received a CD which had about 151 photos on it, but so far you've only printed out 24 of them.
You can keep the cost down of printing out the photos though by printing them yourself (or on a friend's printer) or even probably at Kinko's etc (they will print the contents of CD's for you, and you could choose photo paper if you wanted to make them the best quality--don't know how much that would cost in total though). If you print them yourself, you need only access to a color printer plus a package of "photo paper" you can buy from an office supply store for example.
If you're using someone else's color printer, you might want to reimburse them for at least some of the ink you'd be using up though for that many prints.
You might (or might not) need to arrange the photos from the printer's software (or from Word, or a photoeditor that's already on the computer) on the photo paper so as much of the each sheet would be covered with photos as you could.
Not sure you'll be saving much though from 20 cents per photo even if you print them yourself with photo paper!
P.S. If you wanted, you could also improve the pics or turn them into something else using a photoeditor--even one online.
One possibility, if you have a bw (or color) printer that is connected to a computer, would be to use one of the photoediting sites online, then choose one of the "sketch" or "outline" (could have other names) effects for a particular photo. That will turn the photo into a line drawing, for example, which could then be printed out onto plain paper at home (not needing photo paper), and you could use a few of those instead of the original photographs. You could even color them a bit with colored pencils if you wanted. They'd look quite cool too.
Some places you can do things like that would probably be listed in my answers to these previous questions:
https://answersrip.com/question/index?qid=20101119163455AA5pAwO
Good luck!