I've only done a 4.0. They are not expensive at all. I got a complete kit for less than $10... Most autoparts stores will have them. I used stainless steel, but some think brass is better. I'm not sure I have an opinion one way or the other.
The only issue you are going to have is... having enough room to get to what you need to. The 4.0 was easy. Fortunately, I didn't have to do anything with the one at the rear of the motor.
There are kits to rent (autozone) that will greatly assist you with removal and installation.
You may consider googling 'freeze plug (expansion plug) removal/installation'. There are lots of good articles.
IMO the most important thing to remember if you are doing it yourself is to make sure you have a clean and dry hole before you set the plug. I used Indian Head glue on mine.
[B]2008 Jeep Wrangler X
[B]1997 Jeep Cherokee Country 4.0L/AW4