Judging from the Google results, this is mostly a term used for women's clothes. Here are some links: http://www.expressurway.com/ and http://venusimaging.com/cgi-bin/links/page.cgi?g=Plus_Size_Clothing%2FPlus_Size_Suits%2Findex.html&d=1
There are a number of plus size dresses online. Macy's sell plus size dresses normally for sale online and in stores, although their prices are still quite high.
A person could purchase plus size apparel online or at a mall or clothing store. Many large stores, like Sears or Dillards, have their own plus size departments.
You can purchase plus size swimsuits at any store that retails clothing and swimwear, such as walmart, target, or even speicalty stores like JcPennys.
One can purchase plus size skirts online from various stores. Some of these stores are Old Navy, ASOS, Amazon, Deb Shops, Macy's, Athleta and One Stop Plus.
One can purchase size 12 skirts online from many different retailers that offer plus-sized clothing. Some of the places that offer size 12 skirts online are: Target, Sears, and Talbots.
There are many places to purchase plus size sports wear, including sports bras. One of the best online stores to purchase these is Catherines, which is a women's apparel store.
A plus size blouse can be purchased at various stores that cater to plus sized customers, which can be found in malls and outlet malls. They can also be ordered online.
You can search for plus size dresses on the web. Many of the high end designers have plus sizes so if you prefer a certain designer, you can search their website for plus sizes.
Men's plus wear swimwear can be found at a variety of trusted online retailers such as Land's End and Swimoutlet. Another online retailer is Bcoutlet.
Plus Athletic online has plus size ladies golf clothes in sizes XL, 2XL and 3XL. Loris Golf Shop has a large selection of women's plus sizes. Their clothes are very colorful.
you can find attractive plus size clothing from my moms and all her friends's favorite site http://www.lanebryant.com/ to find your stylish plus size clothing :)
You can buy a plus size dog costume for your dog from Walmart. WalMart is a store that sells many items online. You can purchase costumes from WalMart and they will have it delivered to the store for free or to your home for a nominal cost.