Finding sports logos is not at all difficult to do. Finding sports logos that you can use freely without facing potential legal action is another story. Always make sure that you follow any guidelines regarding copyright law.
Of course, if you want baseball team logos (for example), you can go to majorleaguebaseball.com and find the logo of any major league baseball team right there on the site itself. If you cannot find the logo of the team on this website, you can certainly find it by going to the individual team sites and searching for it there. You can find plenty of team-authorized gear that has the team logo all over it. You can even find stickers with your favorite team's logo. You can buy and then download those stickers for around twenty-five or thirty dollars per package.
This may seem like a high price for stickers, but you have to realize that you can do many great things with them. You can use them in many ways to show support for your favorite team. You can put the stickers on your bike as long as they don't obstruct the safe riding of your bike in any way. You can also put these stickers on your bike helmet, which you should always wear while riding your bike. This is a good way to look stylish and sporty while doing a fun activity. Exerting physical effort while supporting your favorite team is almost always a positive idea.
If you are more of a basketball fan than a baseball fan you can always go to NBA.com to find the logos of your favorite basketball teams. Teams like the Atlanta Hawks will hand out plenty of stuff with their team logo on if you actually go to a game at Phillips Arena. The crowds there at Phillips Arena are rather sparse most nights during the regular season. This means that many of the players truly appreciate some of the great fans who do come out to support their Hawks, and the players will also often be more than willing to sign anything with the team logo on it.
Just like with baseball and basketball, you can find football or soccer team logos on the national league websites. Just make sure that if you plan to use a logo in a public forum, such as a website, that you get permission for such use - especially if you stand to profit directly through use of the logo (for example, making stickers or t-shirts for resale).