First thing's first, do you know how to properly take care of a degu?
That they are prone to diabetes and can not have a sugary diet? No fruit, rat food, hamster food, gerbil food, etc?
Have you done your research about them? They are not 'easy' animals, like hamsters. They are unique and need special care. Degus can live up to around 9 years, so you have to dedicate your time to them.
Also, I recommend you not to get a male/female pair, because they will mate and mate and it will shorten the life expectancy of the female, plus you will be stuck with quite a few baby goos. And unless you'll keep them all, you need to find great homes for them with people who also know how to take care of them.
And pet stores such as PetCo and Petsmart do not sell them ever since the prairie dog madness, and if you ever happen find any there, DO NOT BUY THEM. You, and they, will be lucky to live past 2 years. Same goes for chinchillas, hedgehogs, etc. They are rarely ever put in the store in good condition, much less cared for properly while in the store.
You might be able to find degus in shops near big cities. For example, Chicago and the north suburbs. Since people often know more about degus in those areas, rather than any other area. Also check places like Craig's List and similar. Check the classifieds in the newspapers, etc. You might be able to find someone who will let you adopt there degus, because they are unable to care for them.
And it all depends on who's selling the degus, about the price. They could be anywhere from $15 to $50. It all depends. For someone who is giving them away to a responsible owner, it might be around $100, but that's because they'll supply the cage, food, bedding, dust bath, hay, toys, water bottles, etc, etc.
Here are some sites you should check out.
http//www.degurock.moonfruit.com/
http//www.degutopia.co.uk/
http//www.paw-talk.net/forums/f12/
http//degus.com/babydegus.html
(Also, at this specific moment in time, the Wikipedia article about them is pretty accurate. But I assume as soon as I mention this people will vandalize it.)
Good luck.
-Jessica