>>527289686.
The reason people recommend pulling for the standard banner almost exclusively is because you have a small chance of getting a L/D unit, which are worth about three times as much as a normal SSR.
Although it makes economic sense in theory to pull exclusively in the standard banner, it's inevitable that a character that you either like enough or is good enough will release, and pulling on the limited banner for them might even make financial sense, especially if they make your team stronger.
Freya is top tier in both pvp and pve so pulling for her isn't a loss at all in fact since you just started it might even be ideal. Especially since the game is quite generous and you will get plenty of pulls anyways.
As for how much to spend save, I think you should pull on until you get at the very least two more SSRs. Or you can wait a day and pull for the character that is about to release on the limited banner tomorrow. She is supposed to be pretty damn good as well and looks a bit similar to Freya visually so you will probably like her.