Total Newbie help please with lens selection

Looking to shoot my son's (9years old) basketball this summer. I need something economical (read cheap) that will give decent indoor basketball shotability. I'd like for the lens to be as flexible as possible aka useable for other things not just basketball. Would I be better off with a used 85 or can I get away with one of the cheaper zooms with IS? I do not expect magazine quality photos just home user/fond memory makers.

Camera is a Canon XSI with standard lens.

Yes, I searched but found no definitive answer for the price range.

For indoor sports, the cheapest solution will be a fast prime, like the 85 f/1.8. If you can get pretty close, the 50 f/1.8 might work. IS isn't going to help you with freezing action, and the cheaper zooms are way too slow.

Welcome to POTN. The 85 is almost universally recognized here as an excellent lens for indoor basketball shooting. IS won't help for what you're planning to shoot.

EDIT: Just a tad slow.

I think a used 85 would be a great choice. It will be the cheapest/fastest lens you will find past 50mm. It also has ring USM, which will help with sports focusing.

Also consider the 100 f/2 which usually runs a little cheaper than the 85. Identical lens almost.