Welcome! I am new to MN myself, though not new to the hobby. There are potential pitfalls, of course, but many wonderful Ladies here, and marvelous experiences to be had. Misty, Nora, Tuzdae, Marissa, TJ, and the Ladies of the MGC all have great reputations. There are more, forgive me if I have neglected to mention other great MN Ladies.
Check the TER Escort Reviews. Even if you don't sign up for the Juicy details, you can get a good idea from the number or reviews and the ratings if someone is popular and well-liked. With the details, you can try to assess if a Lady's style and "menu" are what you like.
With any reputable escort, the price quoted should be all-inclusive. Incall is included, if that's how she operates. For outcall, transportation to your location is included, although if you are outside the Metro Area, you might reasonably expect a modest surcharge for the extra time and expense to travel to you.
Again, with reputable Ladies, a tip or other gift is usually appreciated, but never required. Once you get to know a Lady, you may have an idea of a thoughtful gift she might appreciate. Otherwise, cash is always nice 
As for being found out, that is a whole 'nother story. I am single, and I'm not in an especially sensitive sort of job, so I tend not to worry much. Perhaps some of the married guys, clergymen, and elected officials in the group can help you out 
In general, learn how to clear all evidence from your computer. Even if no one else has regular access, you never know when someone might sneak a peek. There is plenty of software available to handle this - search the WWW. Also watch for a "paper trail" on things like TER Membership, etc. Best to pay cash whenever possible, or use Postal Money Orders, etc. Both financial records and computer records can be subpoenaed by a divorce lawyer, if it ever comes to that.
Watch out for perfume, lipstick, etc. One chap I know suggested that on the way home from seeing a Lady, stop and fill your car with gas. Intentionally spill a few drops on your hands - the smell of gasoline will cover up anything else, and it gives you a good excuse to shower, if you couldn't do that at the incall place.
And, most importantly, WIPE THAT GODDAM SMILE OFF YOUR FACE!