i had a lawn customer ask me to put some stone in her back yard. she didn't ask for a price, she asked what kind of stone i recommend, then said simply, "ok, do it." well, i told her i'd get to it when i had a chance. i didn't plan on it today, but we ended up there, it's only about a 3-4 hr job, and it's a shady back yard, being it's so hot, i decided to do this job today. well, it was spur of the moment, so i didn't write anything up. she never asked for a price. i'm afraid she may faint when i hand her the bill for $900, and tell her, " NOW, it's due NOW". bad move or what? is it ok to do a job, without telling them how much?