He cleared $6M of cap space, this year and next, without giving up his 1st. Not bad. 
- Cooleus
Cost in the league for doing this is tied to salaries. So, for example, Minnesota taking on 3 months of a 1/4 of ROR salary = a 4th round. That is 1.8 million for 1/4 of season. Extend that onward....Zaitsev is 6.5 million over the next season and 1/4. Definitely worth a 2nd and 4th given market value.
And I think the Sens got off cheap getting rid of Murray for a 3rd and 7th. Just look at him now in Toronto - hurt, headcase, frustrating, can lose 2 games for every game he steals. Everything he was in Ottawa. Go riddance to bad rubbish. The draft picks are the cost.