The most reliable source I’ve ever used is Amazon. The product ships from Amazons fulfilment warehouse which is owned by Amazon and is prime eligible (2-day free shipping). They offer no questions asked returns/refunds/exchanges and they’ll cover all return shipping costs for refunds/exchanges.

Also: if you return to Amazon: they send you the waybill for shipping and you typically have 30 days time limit for them to receive the return or at least confirmation it’s been shipped. I’ve many times returned something to Amazon about 18 days after I ordered and received the replacement.

I’m also a vaper which means I did some pretty intensive research regarding batteries due to the potential catastrophic failure that can occur in a vape if used incorrectly. I found quite a bit of info on how frequently even vape shops will sell knock off batteries labelled as premium.

Two weeks ago I bough 4x 18650 flat top Samsung 30Q from Amazon. Arrived in 2 days:
-The batteries came in clear 18650/18350 plastic battery cases (2x18650 or 4x16340 cases)
-Plastic carriers were inside a 3.5”x3.5”x1” flip lid cardboard box
-The 3.5” cardboard box was shipped alone inside a 12”x4.5”x8” cardboard shipping box with a huge 6”x4” LI-ION DANGER blah blah blah warning label

Amazon is consistently less than any vape shop I’ve checked (at least a half dozen) but more expensive than BG or GB (which won’t ship to Canada).

Amazon doesn’t however offer ANY button top batteries as from what I’ve read, these are modified in house by the seller which Amazon isn’t offering.

I’ve also just placed an order over the CNY that hasn’t shipped yet from Nealsgadgest which didn’t restrict me from buying 4x 30Q button tops. Hope it ships! If not Amazon’s got your batteries.

Amazon today: (prime eligible) 30Q 6 pack $62.86 or $10.48/ea
Nealsgadgets: 30Q 2 pack $18.09 or $9.05/ea
digitalimports (vape warehouse): 30Q singles (when available) $15.00+ ea