Budget priced tootle tanks that are easy to build:
Taifun GT2 (clone as authentic is $180)
Hurricane clone (the authentic is $175)
Original Lemo or Lemo Drop (on clearance for about $16 now and IMO better than a Kayfun)
HCigar HC Plus ($20 at Froginfog)
UD Aga t5 ($10 at Triangle Vape, and maybe VapeNW?)
Nectar clone ($9 at Focalecig, authentic is $145)
Ataman 2 clone ($25 at Froginfog, authentic is $120)
Harder builds, but awesome:
Rose v2 or v2-s (clones are $20-25, authentics are harder to find and about $190)
Taifun GS2 or GSL (clones are $18-23, authentics are $140+). Only harder due to needing to make mesh feeder straws. The plastic tubes that come with them caused flooding for me.
Flash e Vapor (clones about $25, authentics about $140 with shipping). Again, need mesh feeder wicks.
eXpromizer. Easy build and awesome vape. Authentics about $60-70. Not sure if there is a clone.