Tell me about it. I'm glad I started collecting equipment before I got disabled. Now I'm struggling to keep my head above the water and it isn't easy. I, too want off disability.
Now as far as celeb pics & such.. you can't unless you have their permission. Anything copyrighted you can't touch either unless you have a license to use them.
Now you can get preprinted transfers from places like proworld and transfer express. You will have to have a business license - have to keep it legal.
You can get a website for pretty cheap and sell there. If you get an e-commerce website you will have to pay, or you can get a free website, but they usually put annoying banner ads on your page.
Do you have a printer and computer graphics program like coreldraw or adobe illustrator? You can get coreldraw pretty cheap on ebay, just make sure you get a full version not an educational or upgrade one. Are you going to be printing your own things to press or no?
You will need an epson workforce 1100 printer with pigment inks (I suggest getting bulk ink and refillable carts from cobraink.com). It might take several months of saving pennies to get what you need, but hang in there.