I've been a cubmaster for a while and I've never charged den or pack dues. We cover all operational costs with popcorn sales and avoid having parents pay anything for the program. I introduced an optional once a month program night this year that costs $5 to cover materials, belt loops, and pins (the program focuses on Sports and Academic pins since they are going away) and I've already had parents complain to the committee chair about why they are paying for this.
So relatively speaking paying $50 for pack dues and $40 for den dues annually seems really high, but if the pack does no fundraising I can understand. We make between $7000-9000 net from popcorn for a 65 boy unit, if that helps understand our situation.