Good place to start:
http://www.ci.richland.wa.us/RICHLAND/p ... N=62764811
Then head down to the building department (behind fed building) and get a plot plan of your lot. This will tell you were the house and easements are.
Now comes the fun part, trying to figure out how to cover 25% of the back yard with shop avoiding easements. Depending on the lot it can be very restrictive in shop size. Easements can be easy or troublesome but it all means more paperwork with the city.
The shop should be 3' from the property line, UNLESS you put a fire wall up then it can be against the line. I wouldn't recommend any closer than 3' incase you get into a spat with the neighbor, could be hard to get at that part of the shop.
Height also comes into play, 15' is max., this is measured mid slope. My shop has a peak of just under 17' with a 12-3 pitch. Powerline also become limiting factors and you must be 3' away (under) them.
Might want to look at how your going to get power to it too, look for the closest power pole or is it going to come from the house. I ran a second meter underground.
I'd guess a 24x24 pole building with electricy will cost in the 20k range.
I put up a 28x28x12 pole building with commercial girts about 2 yrs ago and paid 2 yahoos (friends of friends) 15,500 for the buidling & concrete, this was about 3k less than any bids. I've done all the electrical and have about 1200 into it and still need better lights. I also don't have any insulation or sheetrock up either, YET.
Then don't forget about your permits (~400 for my shop) and hook-up fees (275 for elec) either.
OH YEA, don't forget to call you dig line. I didn't and the first hole they hit something. Turns out it wouldn't have been found anyway because it was an abandon steamline, but it sure got the you dig lady all excited when I did call.
If you need help, let me know, I can probably help point you in the right direction.