I've actually thought about this as the 510 gets extremely hot with the airflow completely open. Any suggestions...as I'm now in a budget because of constant coils purchases
The Crown was suggested earlier in this thread. I have one, but only use it with a rebuildable deck. Wicking can be a bit tricky.
At the risk of inviting wrath
A cheaper option, is the Kanger. I have 4 of those, and they have never failed to deliver if wicked correctly. Keeping in mind I build my own coils.
Building your own coils is by far the easiest way to save money. I haven't bought coils or juice in over 6 months. And the only factory coils I own, are simply backups when traveling.