To be honest to get an SR without money is quite a bit of work unless Aeria does another event that leads to winning an SR, the last one that comes to mind is Planas Dragon.
However it takes a lot of time and gold to get to an SR using the Fusion+ Chain route.
I wish you luck!
Example of a smaller chain would be:
Gwendelle > Gwendelle+ > Gwendoline > Gwendoline+
Therefore you would need 8 Gwendelle (R) to make a Gwendoline (SR+).
Instead of the longer chain such as Clover Nymph which to get the final SR+ form is 64 Clover Nymphs.
Just in case it's still a bit confusing why it is 8 Gwendelle to make Gwendoline+, here's a quick chart I made.
PS I have a Fusion+ Chain
post that has a few of the Chains there.