They are rechargeable. $14.00 for a battery once or twice a year is cheaper than $60 for a mod once or twice a year.
*some batteries are cheaper, but i don't recommend cheaping out on batteries. Buy the best you can get... if you go that route.*
Can't help much with the built in battery mods.. I don't even look at them. I prefer total control over the brand and quality of batteries i vape with. Plus, like I said.. $14 is cheaper than $60 when they finally do need to be replaced.
Either way, no matter what you get, Im pretty sure we can tailor a cloud build for the gear you get. (as long as it isnt a mechanical mod.. I never suggest coil builds for another persons Mech mod, unless it is within CDR)
By the way, if you really want to max your clouds, you can get pure 100% pharma grade VG at some local pharmacies. No flavor and no nic. I sometimes add a couple drops of mint or licorice to give it some taste. (those 2 flavors seem pretty strong, so I don't use as much, which keeps me close to 100% vg)