Avoid a wedding dress disaster
1. It's important that I find a good one
2. I'm not an expert enough to know myself who is a good one
3. The industry is full of advertisements and misinformation
4. I wish I knew what experiences other people have had
That's very difficult to answer without seeing the house. As one poster said, the prep is the most important part. On newer homes that don't have a lot of peeling paint, the prep can be very minimal even as low as a couple or a few hundred dollars for the prep labor.
On a 100 year old home with 12 coats of peeling paint on it, then the prep costs can be very high and can easily exceed 50% of the job's labor cost.
A 2100 sq ft two story home could easily cost $1000 just for the labor to prep for the paint job. That number could climb too. Throw in lots of caullking or window glazing, and you could be talking a couple or a few hundred dollars more for labor.
Painting that home with one coat of paint and a different color on the trim could run roughly $1000 or more just for labor. Add a second coat and that could cost close to another $1000 for labor.
For paint, you may need 20 gallons of paint. You can pay from $30-$70 for a gallon of good quality exterior paint. The manufacturer of the paint should be specified in any painting contract. Otherwise, the contractor could bid at a Sherwin-Williams $60 per gallon paint and then paint the house with $35 Valspar and pocket the difference. $25 dollars per gallon times 20 gallons? That's a pretty penny too.
That was the long answer to your question. The short answer is $2000 to $4000 and up, depending upon the amount of prep, the number of coats, the amount of trim, and the paint used.