They'll charge you enough that you will not have saved anything by the time they are done.
You'd need to buy some tools and do some reading but nothing on it is that hard. You can find all the instructions to do what is needed and how to do it at
www.parktool.com/repair . Just hover your mouse over the parts you are wondering about and click when the right flag name pops up.
The only custom tool you may need is a pedal wrench. They often need a much thinner than typical general purpose wrench. Or if you have access to a grinder you could use it to thin down a regular combination wrench to work as a very nice pedal wrench. Here's how to shape it.
One last item. A lot of newbies will tend to want to over tighten the small 5 and 6 mm machine screws typically used on bike stuff. You don't need to twist it until it snaps. If you are using a regular length L shaped allen key you can achieve a good safe torque with only two or three fingers on the wrench very easily and the pressure from the wrench should not be enough to hurt or leave a significant mark in your fingers.