Artists have also bills to pay. Not everyone, but many of them sell their work commercially. Some of them are full-time artists, working freelance. If they don’t sell enough copies of their work, future projects might be cancelled.
From our point of view, you should have the possibility to preview these contents. If you like the work and if you are (in terms of money and nationality) able to, support the artist by buying copies of their work.
First a bad message: the way how to buy the copy varies from artist to artist. In rare cases it is almost impossible. But don’t let it get you down, in some cases it is very easy.
These three factors are important: payment option, censorship, printed or digital copy.
Western artists: they have comfortable payment options (a credit card is all you need) and their work is usually uncensored (only totally retarded western artists censor their work). But unlike yaoi artists, they don’t really have a common place to sell their work. Some titles are available via Amazon.com, but Amazon don’t list them in their books department (only findable via search or direct link). Some artists sell copies and also originals in their own shops, like IcemanBlue and ClassComics. IcemanBlue also has its own paysite.
There are also other possibilitys to support, like commission the artist to draw one of your ideas (offers are findable on the artists sites like on DeviantArt, Y-Gallery, AllGayArt, FurAffinity) or buy fan-stuff, like artist-designed T-Shirts and Cups. It is always a good idea to visit the artist homepage/blog (if available) or DeviantArt- / Y-Gallery- / FurAffinity-profile to get a overview about all these possibilitys. We usually link them in our blogposts (please ask if there is a link missing).
Yaoi artists: they have marketplaces, where doujins, games and CG-sets are foundable. The bad thing is that the marketplaces have different censorship demands and payment methods. Most of them are also only japanese. Here is a list with the most popular:
http://www.digiket.com/b/ (japanese language, possibly largest source for material) [only functions with digital money, eg BitcashEx, Webmoney(?)]
http://mk2.surpara.com/ (japanese language, less selection then digiket) [no credit card restriction]
http://www.dlsite.com/maniax/ (english language, useful alternative, pixel-censor) [mostly straight material, selection possible]
https://www.biggym.co.jp/shop/goodslist.cgi?in_kate=40 (doujin & books) [no international shipment / payment]
http://www.rainbow-shoppers.com/jp/index.html (doujin & books) [yes, international shipment / payment]
http://www.toranoana.jp/ (doujin & books, mixed content) [no international shipment / payment]
http://www.c-queen.net/ec/ (doujin, mixed content) [no international shipment / payment]
It is also useful to visit the artists homepage to get an overview about the marketplaces the artist uses. In general, we already link to the works marketplace.
Please note: all these works are usually japanese, only brave scanlators and translators make english translations possible. You can support them with a donation (like a PayPal-donation for Leon).
Thank you for your attention. If there are some mistakes or suggestions, feel free to share them in the comments!