Forget the cost of the item, yes it is a shame.
The advice above is clear and very good to get you back to at least having a shot at getting your glider into better shape. We can't verify the age. But the nutrients that you have described are not going to keep him going very long.
Pedialyte in it's original package only lasts for 24 hours refrigerated and must be tossed after that. It should be given by medicine dropper as well as offered in a water bottle or bowl, but must be changed out frequently.
Take a look at this page
www.suzsugargliders.com/helpforrejectedjoeys.htm
that will take you through the basics from a very young rejected joey through to the age that they will be self sufficient. You may be able to use some of the tips for your glider.
First and foremost. You need to find an exotic vet who is VERY experienced with gliders. It isn't always easy and you may need to travel a distance to them. But, a good vet will be able to verify the age and the needs of this glider in order for him to thrive. There are other factors just as important as his hydration and proper diet, such as the presence of parasites or disease that a vet will need to determine. Check into your area immediately to find a good vet and do what you can to get him there.
In the mean time look at the advice above and also look at the gliderpedia tab above in the diet section which will give you much, better over site and ideas as to what a glider needs to be consuming to stay healthy. This is of second of importance as to getting him to a vet.
In the interim, offer the foods advised above and find a vet that will be able to see him and advise you further. His life is worth it...not the $225. Sorry, but it's a life. Right?