By "lifetime donations" I mean they look at your current level of membership and then move you forward or back in line, within that membership level, based on how much money you have donated during your lifetime. Cougar Club membership does not get you cheaper tickets. And, of course, the better seats you get priority for are more expensive than seats further back.
I would recommend you get a ROC pass if you're planning on going to 3 football games. IIRC, the fee is around $150. And for that amount you also have free admission to the other three games (if you decide you want to go) and free admission to all other campus sporting events (basketball, men's and women's volleyball, soccer etc.). As I understand it, men's basketball is on a first-come-first served basis and you might not get in to Gonzaga or one or two of the other games if you aren't early enough. But otherwise, you're getting in to every game you want.