The information you shared is quite useful. Currently, I only play by renting cards each season. I roughly spend $5 on card rentals and $2 on Wild Pass. With that budget, I am enough to get Chaos edition level 8 summoners and play comfortably between Gold 1 and Diamond 2.
I'm not clear on how much it would cost to rent a competitive deck for Modern Ranked mode, but the rewards there are vastly superior to those in Wild mode. The problem is that, checking prices, level 4 summoners for Modern usually cost about the same as renting a level 8 Gold Foil from the Chaos set for Wild.
My question is: how hard is it to stay at Gold rank in Modern Ranked using level 4 summoners? Is the difference in deck power so noticeable that it's worth the extra expense, or with level 4 summoners can you compete well at that rank?