Would Selling square mlb,nfl, or nhl stickers as "wallet skins" be considered Copyright infringment?

The following is not legal advice and should not be relied on to take or refrain from taking any action. The short answer is no. Assuming that the company from whom you would buy the MLB, NFL, and NHL stickers truly has licenses from those organizations to sell the stickers, then what you would be buying is (1) the physical stickers and (2) the right to use the stickers. The company's licenses from the MLB, NFL, and NHL very likely permits it to sell you as many stickers as you can buy -- but only for your own personal use. The company's licenses from the MLB, NFL, and NHL very likely does not authorize the company to grant you a sub-license to resell the stickers affixed onto a product. The acronyms MLB, NFL, and NHL and those organizations' logos are trademarks. Without a license from those organizations it would be unlawful for you to affix stickers containing their trademarks onto a "wallet skin" or any other product and then offer the product for sale. The company from whom you would buy the stickers may, however, have the right to sell the stickers for resale. You'd have to ask that question to someone in its management -- not a clerk -- and, if it does have that right, you would have to negotiate a sub-license agreement. Before you even begin that process, however, you need to speak with a business attorney licensed to practice in your State to assist you in formally setting up a company and then to assist in any discussions with the company that would supply you with the stickers.

I agree with Mr. Ballard as to the sticker issue. As for the website - if the domain name is available you are free to register it.

The previous answers posted to this question are generally accurate as far as they go, and under the assumptions that they make. However, they don't specifically address the question of whether it would be copyright infringement to take already-printed authorized stickers and then re-sell them. The answer is probably NO, it wouldn't be infringement. That's because the "first sale doctrine" would probably apply. This means that once the licensed manufacturer sells the printed stickers, that "exhausts" the copyright, and so the copyright law would not prevent them be resold without any further obeisance to the original licensor.

In the immortal words of Tina Turner: "What's Copyright Got To Do With It? - Got To Do With It?" The issue is whether the MLB, NFL, and NHL trademarks can lawfully be affixed to a product for sale. And the answer is no absent a license to use the marks from those organizations. Can someone buy the stickers and then re-sell them (as stickers) without infringing the organization's copyright in the stickers? Sure. But if Gerry is suggesting that that re-sale right (under copyright law's "first sale" doctrine) permits the purchaser to lawfully affix those stickers to a product and then sell the product I respectfully -- and strongly -- disagree.