Random Shirts sells funny t-shirts. Like other t-shirt sites (SnorgTees, T-Shirt Hell, etc.) Random Shirts wants people to submit funny or clever shirt ideas. If your shirt is selected for printing, you could receive your choice of $99 or five shirts.
One thing to be aware of when submitting to Random Shirts: your shirt can be used publicly (posted on Facebook to see how people like it) and you may not receive anything for it. From the site's terms and conditions:
All submissions made to Random Shirts become the property of Random Shirts and may be used without further permission by the submitter and without compensation to the submitter.