This community is the reason I found out I was wearing the wrong bra size. Please feel free to make a post there if you need help getting started. Their sidebar has a wealth of information when it comes to finding a bra that fits you perfectly. Instead of spending a lot of time teaching you the ins and outs of finding a good bra, it’s easier for me to link you here.
BigBoobProblems on reddit
This community is run by a lot of the same people who run ABTF, and it’s a great place for busty people to joke, rant, or just generally express their feelings when it comes to having a large bust.
SmallBoobProblems on reddit
This community is much like the one above, except they’re the opposite side of the coin. This subreddit is not as active as BBP.
Bra Band Project is a great way to see how properly fitted bras look on real women. It’s commonly used to show people that sizes like 32HH are not huge porn star sizes, and they’re much more common in the world than you’d think.
The encyclopedia of bras. I use this website to write reviews and compare the measurements of bras to find an easier fit. I’ve started using this more than ABTF because it’s extremely convenient to have the bra measurements at your disposal.
I used this website a lot in the years past because I was really insecure about the shape of my breasts, and I wanted some perspective about how other women’s breasts look. Be warned that the bra sizes listed on this website may be inaccurate.
This is a great glossary of all the various bra terms that get thrown around on this blog. It’s written by Breakout Bras, which is one of my favorite retailers. Make sure to check out the post about root heights and widths. It’s very useful.
This glossary was written by The Petite Collegiate, and is one of the best posts I’ve ever seen that was related to boobs and bras. I think everyone should check this out if they’re confused by anything bra related.
Where I Buy My Bras:
BraSwap on reddit
Where the users of ABTF sell and swap their unwanted bras.
RandomActsOfBras on reddit
Mainly focusing on dirt cheap bras for people that can’t afford them.
Where the users of Bratabase sell and swap their unwanted bras. I prefer using this than Braswap because the measurements and review are right there, and you can see what other kinds of bras worked for the user before making a purchase.
A UK based website that ships internationally. They sell a lot of Curvy Kate bras, as well as their sister brand Flirtelle for extremely reasonable prices.
US based retailer. You can find a lot of bras on Zulily really cheap. Mostly discontinued bras, as well as the brand Kris Line.
US based retailer. Sells lots of UK brands. The fun thing about this website is that they sometimes have Grab Bags in which you can buy a few bras for really reasonable prices. (Like $60 for 4 Panache bras!)
Amazon is great for when you’re not sure what bras work for you because returns are pretty painless and most bras qualify for free shipping. If you search really well you can find good deals (like a Cleo Minnie for $12)
Great for buying and selling used bras. Be careful when ordering to make sure the seller isn’t using US sizes in their listings.
There’s plenty more resources out there, but these are the ones where I’ve found the best deals.