Where to buy

AmiAmi
Ships figurines, eroge magazines, artbooks, anime merchandise and otome games international.
AmiAmi is always sure to get the limited edition of the games and often comes with a special pre-order bonus such as DramaCD or poster. Their prices are reasonable and there is 5 different shipping options, from super fast (but expensive) EMS to cheap but slow SAL.

AmiAmi also sells Eroge, BL and 18+ otome games. You need to click the 18+ category once first before searching for the game title, otherwise it won't show the items. They sell first press limited editions and newer games got special bonus item. Prices are cheaper compared to ComiComi. Very recommended!

CDJapan
Ships figurines, otome and eroge magazines, artbooks and otome games international.
CDJapan got, just like AmiAmi, limited edition and always pack their bonus item very carefully. In my opinion got more information about the item, and a larger variety of magazines, games and soundtracks compared to most stores. Very recommended!

ComiComi
The website in completely in Japanese, but Ponytale wrote a guide which is really easy to follow. ComiComi got everything from 18+ otome games to literally everything a BL fan could need. Take creditcard but sadly only ship with EMS so only shop there if your ready to pay.

Amazon JP
Website can be switched between Japanese and English. Got a large variety of things, but not everything can be shipped outside Japan. I've noticed over time that if it got sexual content, there's a big chance they won't ship it. Always remember to check yourself by reading under the product information. Shipping is often crazy expensive, so I never shop from there, but feel free to check out their stock.

If you want to buy figurines and other merchandise, you can always check out other popular shops like HobbyLink Japan, Yes Asia and Hobby Search