i just received 2 prefilled cartridges as a gift. Was told needed a battery for it and they use a 510 thread. I'm guessing variable heat would be best option so I can change heat for perfect hit. Know absolutely nothing about vape pens and was looking for some info on a decent cheap battery or set up, may it be from eBay or a company. Would a ego model be ok like a ego2 or egoT from eBay? 2200 or 1100mAh? I assume I just screw it into the battery set temp and go. Not looking drop a lot on pen or battery don't know if I'll like etc. if I do wouldn't mind investing in something better to use.