T2 = 225k crews T3 = crews after the 225k (I forget how much they are but that include the sci-fi buff)
Tier 1= 1k crew Tier 2= 225k crew Tier 3= 16m crew Tier 4= 600m crew Tier 5= 10b crew The more expensive the tier, the stronger the crew. Also certain crews are unlocked only after you unlock a certain number of dorms. For mire detailed info you can refer to _Warrior's Guide to dorms and crews, under the Strategy section of Forums.