1) Any worthwhile developer sounds expensive when you break it out as an hourly rate, so don't. Charge a weekly rate tied to specific business goals which you think you can accomplish within one week, two weeks, three weeks, etc. If your client wants to dicker, dicker over scope, don't dicker over rate. Dickering over rate will hurt all your further business with that client. If e.g. $21,000 is too much for the budget, tell them what they can get for $14,000 and let them make the call on whether $7,000 is worth not getting $DIFFERENCE. Whether it is or isn't, it doesn't chisel anything out of your next engagement with them.
An amazing truth about the world: $X00 an hour is a lot of money, but $X00 * 160 for something which makes a meaningful difference to the bottom line of a real company is cheap at the price. Their pricing anchor will be other strategic initiatives rather than e.g. "You make more than I do!"
2) You bill on a time and materials basis. Basically, my best estimate is that one week of work gets you $FOO and $BAR. What you actually have at the end of the week is what you are due at the end of the week. If you change your mind on scope for $BAR in the middle of the engagement and it doesn't get done in the week, that's OK, subject to availability you can buy another week.
3) The basic offering is "A contiguous block of my time starting at a mutually convenient date in the near future." Things which add business value on top of that cost extra. Want to start working next week? Sure. Costs extra. Want to split the engagement into two parts? Doable. Costs extra. Want support? Wonderful. Costs extra. Want support with an SLA better than "Best effort to answer emails within a day"? Costs extra. Travel? Extra, and you reimburse costs as per your company's usual travel policy. (If I had heard that line a year earlier I would be five figures richer to the detriment of exactly no one. Doh.)