Games Workshop’s moonscape pack is a pretty good value. For under $20 dollars and well under two hour’s time, you can have five nicely detailed 40k terrain craters. These craters are multi-functional. They can be used in Planetstrike to reflect the pre-game bombardments and fires storms, and they can be used in any Warhammer 40k game to show where tanks or fortifications blew up.
In game terms, and subject to players’ agreement, craters typically convey a 6+ or sometimes a 5+ cover save as area terrain. They may or may not be considered difficult terrain, again depending on the wishes of the players. You can also purchase warlord games via online sources.
The craters paint out really well right out of the package. You can pick up the crater to a higher level, however. You can mount or support crater on durable MDF Formica or other. You can add rocks and gravel into the crater to make each of them more unique and more detailed.
And you can add a 40k battlefield detritus (of your 40K Bitz and Bits Box) leave from any crater and destroyed in the fighting since then. To cut MDF, first place your crater on MDF and outline the shape you want with a pen. Then use a jigsaw at a 45 degree angle to cut shapes out – angle should slope away from your center. Glue the crater to the MDF by using glue or contact cement.