Well, I think it's a lot. That's more then it costs of the gears themselves. If you went with expensive Spicers or 4.88's you'll be looking around $400-450. I know a lot of shops will charge that and have you buy gears through them so they make even more money. Places like 4WPW will charge around $1100-1600 for a complete job.
What kind of shops are you calling? The best places to check for decent prices is a speed shop. Not a import shop but an actual speed shop that focuses on hotrods and race cars. They should be able to do it cheaper and faster the a 4x4 shop. If you take the axles out of the Jeep, they might even cut you a deal since it won't take rack space and they'd be able to do it on a bench while makes things A LOT easier.
You might check with fellow Jeepers in local clubs. Sometimes one of the memebers knowns someone or owns a shop. The cheapest I've ehard gears done was for around $75 each end. I'd jump on it if it was even $150 though.