Building your own coils and and wicks not only allows you to control the quality of your vape via the resistance of the coil, but allows you to use different materials for wicks as well as saving a ton of money. But it's easier to build coils for rebuildable atomizers like the Kayfun.
A Kayfun clone on FastTech is $20, a bag of organic cotton balls is $2-$5 and a roll of 100 feet of kanthal A1 wire is $5-$6 - and all you need is a PV that measures the resistance of a coil (ProVari, Vamo, SVD, etc) - making a coil takes 5-10 minutes and you can reuse it for 2 months or so and the cotton wick needs to be changed every 15-20 ml of juice. In summary, you spend $30 for a tank and supplies that will last you a year, maybe more - depending on how much you vape.
A ProTank 2 is $20 and a pack of coils is like $5-$8 - this setup will last you a lot less than a year.