Is it ok to drive a truck with a bad coil / spark plug?

Hmm... should i pay a mechanic to check out this van, or just forget it?

I have it scheduled at a shop tomorrow morning. But i don't want to waste the $100 they will charge me if it is clearly not going to be a good van for me.

(BTW, multiple mechanics have told me a compression check on a van would be $400-500, because they have to tear out so much stuff to get access. Apparently checking all the spark plugs is out, too, IIUC. Some are easy to get at and some are buried?)