Yeah, it's a little frustrating. What I'd suggest is, look for someone who's renting out level 25 dragons, then wait until you can afford to rent them for 3-4 days, Use those days to level up dragons to exalt, and if you do it enough (+selling the goodies you can get from areas like that) the rentals should pay themselves off + give you a cushion, depending on how often you can Coli.