We don't have a fixed roller-replacement price to publish here, since it depends on whether you need nylon rollers across all ten positions or just the two or three that are grinding, and whether the track needs straightening or replacing alongside them. What we can tell you is the shape of the decision: steel rollers are the cheaper part up front, nylon rollers with sealed bearings cost more per unit but run quieter and don't need the periodic lubrication steel does.
Given that Lowry Crossing runs a median household income of $110,357, most homeowners we talk to in this pocket opt for the nylon upgrade across the full set rather than patching in steel replacements one at a time - it's a one-time job instead of a recurring one. That's a judgment call, not a requirement, and we'll quote both ways when we're out.