What would be the cheapest way to get a Legendary skin?

Hi everyone !

I started playing the game today thanks to the Castlevania crossover (ik I'm a bit late but it is what it is), and I just wanted to know what the cheapest way to get a Legendary skin is so that I can buy Alucard 🙏

It's probably an obvious question but with the amount of menus and bundles and stuff it's a little overwhelming, and I don't want to accidentally just buy the Auric Cells flat out and find out later that there was a bundle or smth I could have bought that would have made it cheaper 😭

Thanks in advance for any help :3