Idaho Falls is a pretty small community, so there aren’t a lot of options. There is a locally owned soccer (and hockey) shop located at the corner of 1st Street and Emerson Ave called Kicks N Sticks. The owner is normally the one working there, and he is very friendly and helpful. There is currently construction along 1st Street, so it may be easiest by approaching from 2nd Street and turning north on Emerson Ave.
Link to facebook page: https://www.facebook.com/kicksNsticks
The facebook page will provide the most up-to-date directions as construction changes in the area.