I jsut wanted to toss out that there are different types of professional guards out there. I've had the horseshoe shaped ones, I've had that on the top which i pushed out with my tongue and then on the bottom which worked better, my new dentist, insists on this tiny one that just covers two of my bottom front teeth, and it's angled so my top teeth are supposed to just touch it and then bounce right off because it's like a slide and you aren't BITING down on it. Still doesn't work I wear a groove in it side to side. I haven't really found a great solution for me, if your case is different or less severe you might find a night guard solves all your problems.
Personally i wouldn't bother with the boil ones you get from the drug store.
Relaxation techniques might help. I was told NOT to lock my tongue to the roof of my mouth, to actually open my mouth a little so my tongue wasn't constantly pressing, that has helped some. Another thing that i've been wondering about lately --well it's a little weird, I can go all night with out getting up to use the bathroom, but i'm wondering if maybe when my bladder is full if i clench and grind my teeth even though i don't wake up to actually get up and go. I'm considering setting an alarm clock just to get up to empty my bladder and see if that helps. I'm also sure I'm not getting enough sleep and that probably doesn't help. You can research what type of pillow would be best for clenchers, someone recommended a Water Pillow but i haven't taken the time to track one down for myself yet.
I don't remember my costs, but I does seem like maybe checking around is a good idea. My dentist says he can smooth out the grooves i've worn in this little guard any time and i don't even have to be seen, just drop it off and pick it back up.
**** ONE thing I would warn You is to not EVER EVER let them grind down your front teeth to fit a guard. I had a dentist do this with out telling me what he was doign and now I can't bite anything because my front teeth don't touch, plus i look stupid.
I'm sure if your case is mild they wouldn't do this to you, i've ground my teeth for over twenty years so mine were way way bad, but just tell them up front you've heard horror stories and don't want them to file your teeth down.