Pacaya is an active volcano that is currently continuously erupting.
Pacaya first erupted approximately 23,000 years ago and has erupted at least 23 times since the Spanish conquest of Guatemala. After being dormant for a century, it erupted violently in 1965 and has been erupting continuously since then, sometimes showering the nearby city of Antigua with ash.
This is an active volcano where you can get close enough to the lava flows to poke sticks in it. The ground is made up of loose volcanic rock and is quite unstable in parts.
Take a bus from Antigua. I believe it would be safe to do this trip on your own although many people state otherwise so you might want to go with a tour company. Shuttles from Antigua to Pacaya volcano everyday the cost is around $15 US per person.
There is a park entrance fee of Q5 Quetzals.
Walk and take a hiking stick the ground is rocky and in sections it is unstable.
Molten rock, lava flows.
Hiking Stick - it'll cost you less than $1.00 and should be returned to the local children that sold it to you.
There are shops at the base of the trail.
You can camp here.