Officiant - cost and invites?

Hi,

We're looking for an officiant, preferably a judge or justice of the peace.  Getting married in Lake County.

So far, we've found a reverand for $140, retired judge for $375, and another retired judge for $550 - with such a big range, I'm wondering how much I should expect to pay?  What do you think an average price is?

also, do we invite the officiant to the reception? 

Thanks!