Someone taught you well! I knew I liked you!!!
OT: You vape with an 808, correct? How do you like it? If you prefer to PM me that's okay.

I'm quite disillusioned with my 510(s) and looking for something better (tasting - not like plastic!) but in the same price range.
Actually i use a Silver bullet at 6V with Cartomizers. I experimented with 510 atties but for me they just couldnt produce the flavor that i get with cartomizers.
A cheap alternative for you might be to get a 510 to 808 adapter so that you can use cartomizers on your 510 battery.
An interesting discovery has been made on the 510's also. Although they are represented as a 3.7V device the actual voltage with attie attached for vaping is in the 3.0V to 3.2V. That doesnt seem like a big difference but when using a "true" 3.7 device the difference is readily apparent in TH, flavor and vapor.
I started my vaping journey with a kr808 and if you like the 510 with the exception of flavor then i believe you would like the kr808 as well. It wont give you the vapor production of the 510 but its still adequate and it beats the 510 hands down in battery life and flavor from the cartomizers.
I actually did a review between 510 atties and cartomizers. I have no idea where to find it but its on the V4L sub forum somewhere if you care to read it.
Prices vary for blank cartomizers but you can find them from suppliers on this forum between $7-$9 per 5 pack. I would suggest you get at least 10. You can refill them hundreds of times if you wash them regularly and they will vape just like the first time you filled one.