Thats a tough one. What kind ofDumbells to get? If you forego the smaller ones and go with what you do your work sets with... that might help but you don`t really get that much weights even if you started with 50`s. From 50`s to 65`s is already 460 pounds. Damn. it adds up quick. lol
I`m sure you can save money by having the collered dumbells sub 50 then go with the solid ones after that. or maybe go unconventional and skip a sequence like 50`s -60`s - 70`s... and get the 2 1/2 pound magnets for the sides so you can add them at will. Those magnets will double your number of dumbells instantly.
Think about buying 1000 pounds though, If you can. I have the 20`s to 100`s and it`s VERY convenient. It`s for the long haul... only YOU know how long you want to be doing this. good luck