Supplies - Bottles

The "Best" Bottles

First and most obvious; the more you buy, the cheaper they get. But how many do you need? If you're mixing for friends and family, it's worth investing in >100 in order to save in the long run. If you put the Y in DIY and don't feel like sharing, you'll probably get by with around a dozen bottles of various sizes, especially if some are glass (rinse and repeat)

If you're in it to save money and make the same recipes again and again, you'll want a few big bottles to store your mixes in and dole out over time. And on the flip side if you want to go down the rabbit hole and test every flavor individually, test and retest recipes to perfection, and generally just make this a hobby, you'll need tons of little bottles.

Bottles are obviously an important part of the process from storing your bases to the final mix and the options and differences between them can be stifling.

Below I'll try to break down all the available options with their pros and cons, from the collected experience of the sub and my own experience, with a little science sprinkled in for fun.

Types of Bottles and their Utility

[PET] Polyethylene Terephthalate - Is transparent and rigid with slightly less chemical resistance than L/HDPE but has a significantly lower oxygen transmission rate. For practical purposes this means that PET should be better than L/HDPE for long term storage of mixes, flavors and nicotine. The downside of PET is it's rigidity. Depending on the size and shape of the bottle it can make it difficult to dispense its contents and repeated squeezing can cause the bottle to crease. And more importantly there are certain chemicals known to ‘attack' this type of plastic (More on that here)

[L/HDPE] Low-Density/High-Density Polyethylene - Both are highly chemical resistant, flexible and opaque. The primary difference between high and low density polyethylene is actually more about it's tensile strength than actual density.
For almost all practical purposes related to our uses the difference is that HDPE is typically used in larger bottles (8oz+) and most sizes 4oz and under will be LDPE because it is less rigid/more squeezable than HDPE. HDPE is also typically less transparent.
Anecdotally mixes, flavors, and nicotine do seem to be affected by oxidation faster than PET or glass but this should have little impact in the range of 3-6 months.

Glass - Glass is better at everything from oxygen transmission to chemical reactivity, and possibly most importantly, reusability. When it comes to long term storage of mixes, flavors, and nicotine glass is king with one caveat--rubber droppers; "Free volume or "holes" exists in the rubber matrix. "Holes" thermally form and disappear with the movement of polymer chains. Gases are soluble in rubberlike substance. When rubber is exposed to a gas, solution occurs at the surface and the dissolved gas molecules diffuse into the interior. The diffusion of gas molecules in the rubber membrane is a process in which the gas molecules migrate from "holes" (free volume) to "holes" (free volume). The permeation of gas through a membrane involves in solution on one side, diffusion through the membrane to the other side, and finally evaporation out of membrane" In layman's terms (translated by a layman) use a phenolic/polycone cap if you want the benefits of glass to be maintained. Rubber droppers, for our intents and purposes, will lower the efficacy of glass to around the same level as PET/LDPE when used for long term storage of highly volatile flavors (see also: super/ultra concentrates) and high concentrations of nicotine prone to oxidation.

A Visual Glossary of Bottles

• Boston Round: Glass, Plastic
• Bullet/Cosmo Round
• Unicorn
• Flask
• Cylinder
• Yorker Spout
• Twist Spout
• Fine tip

Vendor List

Some of the most commonly recommended places to get bottles including a few examples of what they offer and how much each bottle will cost.

If you just want bottles

eBay

Every type of bottle is available. A lot of free shipping options and be sure to look at where the item is being shipped from because a lot of the options are shipped directly from China (If you've got time for that, they will be cheaper)

Amazon

If you have prime, there are a lot of options for every variety of bottle with prime shipping (and non-prime free shipping)

Fasttech

If you're into unique/weird bottles (e.g. 30ml glass skull dropper bottles) and waiting a week or six for your order to arrive, this is the best place to go.

Hempnetix (Formerly Heartland Vapes)

Most options are for 10, 100 & 1500 bottles. They carry glass, L/HDPE, PET, Chubby Unicorns and have a variety of caps and droppers that can be bought separately. Bonus: A large variety of bottle and cap colors.

Dropperbottles

If you're willing to buy 100 they have a great selection and some of the best prices.

And More

• GlassBottleOutlet
• Liquidbottles
• Berlin Packaging
• SKS Bottles
• Aliexpress
• Packaging Options Direct
• Container & Packaging
• (UK) iBottles
• (UK) Ampulla
• (UK) VapingBottles
• (UK) Lubrisolve
• (UK) The Alchemists Cupboard
• (UK) NaturallyThinking
• (UK) Everything Liquid

If you want a side of bottles with your VG, PG, and Flavors:

Bull City

An excellent selection of bottles perfect for adding to your frequent flavor orders. Prices are decent as an addon to another purchase. They carry a few sizes of glass with droppers or caps as well as a large variety of PET/LDPE bottles and individual twist/yorker style caps.

References:

The Permeability Characteristics of Silicone Rubber
Properties Of HDPE, LDPE And PET Bottles