i think a lot of the places that have anything "free" aren't at the very least being upfront. i think charging the same labor price for estimates is about what i've experieced, and i've done light car work myself (pads, rotors, drums, velocity sensor, heh, can't remember what all, but no like rebuilds or anything).
Anyway... All I can say is I've been going to North End Wrench just north of cooke on the 4 route... and they've always been upfront and honest, and a fair price.
It is possible that with power steering, their may be some non-destructive diagnostics, some pressure testing, checking codes, they could do with a half hour or so in labour. but then to get at the problem, or if it is a systemic thing, they might as well just fix it while they have the thing tore apart, so that's why and estimate may be a moot point, by the time they find the problem.
look for a hose thing to be around 200 max, compressor thing to be yeah like 600.... once you get up into 1500+ you're talking serious engine or drive train things, or entire systems... and then after those three layers of things, there's not much else you can do to a car, hehe ;p