Express Action Sports

I have the Canon Rebel T1i, and I’m looking to take better pictures of outdoor sports as well as indoor events. I currently have the Canon EF-S 55-250mm f/1.4-5.6 IS, Canon EF-S 18-55mm f/3.5-5.6 IS, as well as a Canon EF 50mm f/1-1.8. Would a Speedlight be beneficial? Or more cost efficient?

It sounds like you have the lenses that should do the job. There are of course better faster lenses but they cost a ton of money. What I think you need to do is learn how to use your camera better. A good class in photography and some practice will improve your pictures.

The 55-250mm should do a fine job with outdoor sports during the day. You will have trouble with it indoors or at night because of the small aperture. The 50mm F1.8 should do a good job with indoor sports if you are reasonably close.

A flash is not recommended though. It would be completely useless with outdoor sports as the action would be too far away for the the flash to be effective. Indoors it would work if you were within about 30ft. but do you really want to be sending a bright flash in the athletes eyes over and over again. I think they might have a problem with that.

If you really want to upgrade lenses be prepared to lay out some serious cash. The 70-200mm F2.8 IS lens is nearly $2,000. A 50mm F1.2 is also nearly $2,000 and a 24-70mm F2.8 or 18-55mm F2.8 are over $1,000.