First, gas fireplaces are very safe, especially direct vent gas fireplaces.

Second, fireplace installation primarily requires basic construction skills, so a fairly handy homeowner should be able to handle it. The most important thing is READ and FOLLOW the gas fireplace installation manual. This particular skill seems to be lacking in most do-it-yourselfers . . .

Gas line sizing and installation call for special knowledge and skills, and should not be done by an amateur.

Also, you should have a fireplace professional check out your handiwork and start up the appliance (fireplace) for the first time, for your safety and to validate the manufacturer's warranty.

Construction company should be hired when you are doing any major repaired to your home. Make sure who you hirer has insurance and licensed in the state you live. Check into your contractor ask for references, check threw the state to seeif any charges are brought against him from past customers. The best way to save money is to do the things that are harder and more exspensive to change around later. Like adding things like lighting in a ceiling and upgrade of cabinet material. it cheaper to add these thing as you go than to reap down later. Keep with in the budget on flooring etc. You can update them 5 to 10 year down road when you can afford it.