My first thought, is yes, my friend, hosed big time.........however......average shop rate is about 120 an hour (give or take). Post a picture of your bill if you can. Alignment I'm guessing is 60 bucks. Parts kit is 100 (just guessing). Labor for parts (lets go on the cheap side) half hour per side, so 120 for that labor........so 280 (give or take).....still shy of your posted amount though !
Now everyone is right here, you could have used the write up and done it your self. And there's no guarantees you needed what they sold you......but I'd be curious to see your invoice just to see what they did for that amount, there could be more to the story. Truthfully on a Jeep though, unless parts are out of spec, 60-120 is really the max a shop should charge.