For a cheap RDA from China the link I am posting is good. You may have to file the poss pin down a little as it is really a hybrid RDA and the fact that the center post has slots rather than holes can make trapping thin wire fiddly but other than that it is brilliant. Good flavour, dual or single AF, fully adjustable AF and is also good for TC should you want to...all for £3.67!!!!!
I have one and have just ordered another.........£3.67 posted through your letter box!!!!!! Amazing value!
With ft read the discussions to get an idea of the best versions. You can also get the site to list kayfuns by popularity though this does favour versions that have been stocked for a long time.
For many items with a lot of versions you will often find discusions on which are the best ones.
Just realised the IGO W Plus doesn't have adjustable airflow, but thanks to Totally Wicked giving me a £5 voucher managed to nab the IGO W8 Plus Jaws which does for £4.83 so now have two drippers on the way lol. Gutted as didn't really pay much attention and could've nabbed the Lemo for less than 8.75 if I had any patience