Earlier this week we had scheduled an appointment with Stanley Steamer to have our grout cleaned. We had a coupon for $40 for up to 100 sq. ft. When the guys arrived they told me the minimum order was $69. I showed them the coupon but he pleaded there was no way they'd drive up to Crestview for a just $40. So I turned them away (so apparently they're willing to drive up here for $0). Hopefully they'll fix the coupon.
Anyway, we still needed to get the grout cleaned. Michelle sprayed some Scrubbin' Bubbles over the grout, let it sit, and I followed with a scrub brush. This worked really well and the lines are surprisingly white.
Michelle cleaned the grout once before using some other cleaner, but she said it took a lot more work than it does using the Scrubbin' Bubbles (I think I was "missing" during this first cleaning session).
So that's a relatively inexpensive way to clean your grout. We'll probably do one more application and then use the sealer on it.