try start upgrading until base 15 factories, then get power kits, the rare ones u can use them for upgrade, but for that, u need some food to boost thoses power kits, u can use basic craft to level up the power kits, dont transform your common ones, it just will be a waste of money, and also dont savage rare kits to food another rare one, thoses, rare power kits are the esential to upgrade your weapons and items, and also dont transform up to epic tier, because need more money to upgrade it