buy em from other organization with 3for1 4for1 6for1 trades. I would even go further and say put a emphasis on the lifetime box scores when you have a sufficient large sample size(ie 600 SLG doesn't mean much if the AB's are 150).
Another aspect is getting a sense of the value of the waiver wire. I don't know but looking in the stratonerds keeper league I get a sense that their is a ton of value from career minor leaguers who never got called up for various reasons. Players such as jack cust, scott hairston, dallas mcpherson and gomes were literally waiver wire/ cheap trade pickups two seasons ago. All of these guys had minor league resumes that read "yeah I can hit!".
Ditto for relief pitchers. Their are tons of em out their. And seattle already has a respectable starting rotation with a pitchers ballpark.
It's alot cheaper to pickup a player that was ignored by their team then try to develop one in house.