How much should you spend on a charcoal grill?

Person holding the lid over a lit charcoal grill.

I'm pretty partisan when it comes to grilling: charcoal grills always taste better than gas. Cooking on charcoal makes for delicious smoke that utterly transforms your food. 

However, if coals are the only thing that makes a difference, it stands to reason that you don't need to pay much to get a good grill. It can be hard to know if you're overpaying or underpaying for a good grill.