How much it would cost to get every skin

There are 131 champions right now. there are 689 skins but, some you cant buy in the store. So say if you have another account and mystery gift yourself skins. This lets you get every skin. Mystery gift skins are 490 RP = $3.27 this is at $100 price so 689 X 3.27 = $2,253.03 or a little over a But you can only gift 5 RP gifts a day thats 137.8 days rounding up to 138 days thats $16.33 a day

So over all it takes $2,253.03 or 337,610 RP and 138 days to get all 689 skins