My favorite plastic tank is the iClear16. You don't replace the whole tank, just the coil assembly when needed. With occasional dry-burning, the coils can last a long time. I have three of those going now.
I like a lot of plastic tank cracking flavors so I need glass ( or metal) tanks for those. My choice is the mini Protank 2 or the Davide Mini. There's more of an up-front cost for these, but again, only the coil head need to be replaced once it's done-in. Both Davide and PT use the same heads, so you only have to stock-up one type of spare, even if you have both brands of tank. The real savings comes in if you learn to re-coil the heads yourself. New coil heads run about $5 or $6 for a 5 pack if you catch a sale, but recoiling them yourself gets the cost down very low, under a quarter depending on what materials you choose.
So spend a little more on tanks with replaceable coils up front, but save in the long run compared to disposable CE4 types, just buying the coil heads or re-building.