Find somewhere local, shits ridiculous rn I thought it was bad when a bag of roots was $30, now that shits $40. Go get some peat, perlite, ewc, and dry amendments and do it in store if possible. Premixed potting soils already kind of expensive for what it is, sure Amazon says free shipping, but compare their prices to your local garden center and you’ll see amazons charging you for it. Only difficulty might be actually finding peat. Shits out of stock everywhere.