As jsa said, most owners will start with the "big 3" on defense of Arbour, Harris, and Alex Smith, all costing under $4 million. Some owners will then go with another 90+ rated d man, others will go with 70 or 80 rated d men to round out their top 6. Like he stated, if you are gunning for more offense, Coffey is a good choice at under $2 million with plenty of assists. Personally, I go with d ratings for my d men and don't worry too much about helpers from the back end.
A lot of owners use a scorer, assister, and defender per line when building an offense. You can get great defense from Duggan, Helman, Larochelle, Langlois, all for well under $1 million. (Helman and Larochelle cost $165,000). The thing to remember when building an offense is shooting % costs $$$. Go with a high shots, decent shooting % guy for your top scorers. Assisters and defensive forwards are usually guys with lower shots per game as you want your scorers taking shots when one is awarded by the sim.
To repeat what jsa stated, there are plenty of good guys in the hockey sim who are more than willing to help if asked. If you find once you start that you have specific questions, reach out to the league for help and you will be amazed at how many guys will be willing to help you.
Good luck and welcome to sim hockey rickhren!