I know the basics of model releases and copyrights and all of that, but was unsure about this one. If you were to travel to highschool sports games, take action shots of the players, and then upload to your account to sell to the students, would you need model releases? I was thinking of doing this and handing out some cards, or emailing the coaches to let them know of the website. I know that many people do this, but thought maybe they had some pre-arranged agreement with the school.
Your questions involve the very basics essentials of model releases so you may want to re-examine your belief that, "I know the basics of model releases and copyrights...". A model release protects and defines the rights accorded the model and the publisher of a photo,
not the photographer. Publishers and models expect the photographer to handle the paperwork
only because the photographer is right there when the photo is made. Sometimes, the photographer also winds up being the publisher, but it's not very common.
The basic concepts involved here deal with what constitutes 'publishing' and what constitues 'commercial use'.
As long as the players cannot be perceived as endorsing or sponsoring your 'business', and the photos were made in a public, spur of the moment way, you don't need a model release to display the photos on a business web site because that is not 'publishing'.
Selling photos in small quantities to a limited number of private individuals is not a 'commercial use' (it's not mass distribution), so again a model release would not be needed.
As tirediron pointed out, you cannot rely on legal advice you get in online forums, because it is often based on Urban Legend, not fact.
Model release laws vary by state. In particular the concept of 'Right of Publicity'.
Visit:
Model Release Primer
and get Dan's book
A Digital Photographer's Guide to Model Releases.
Model Release law is not as cut and dried as, say, traffic laws. So very often the correct answer is,
it depends.