Hi Darkie,
siwel is on the right track. Rucks are an area where most Coaches burn 3 to 5 trades a season, and yet they only make up 2 onfield spots in our team. Combine that, with the fact that there is historically a big gap from the 3rd best scoring Ruck in any season, and the 5th or 6th best, and we need to get our final selections right. We obviously want to get them right, with as few trades as possible, so with that in mind, and remembering that a "failed" M2 pick, can still slide down, and do a job for you at M8, but a failed R2 pick has nowhere to go but out, we should decide on our Ruck strategy, and not consider dollars too much. History has shown that taking last years top 2 Rucks at R1 and R2 hasn't been a great strategy, so we don't just burn dollars for the sake of it, but don't shy away from your pick because of dollars. You'd kick yourself if you liked say Sauce this season, but decided to "save" $60k, and go elsewhere, only to see Sauce light it up again this year. (disclaimer - I'm not picking or advocating Sauce this season). It's so important to get your Rucks right, so you don't leak points, and it's important to try and avoid 5 trades to do it, hence they get a special "rule" all of their own.