Living in CA and sometimes owning older cars I have had to take them in for the required smog check every two years.  Many places do these smog checks - they have signs all over the place advertising this service.  The fee for smog checks vary as they are not controlled by the state.  Usually advertisements will tout $19.95 or $29.95 but that is just to get you in the door.  The price will always be more than these advertised teaser rates.  You will pay at least $50 and sometimes as much as $100 depending on how savvy or not one is about pricing.  Make no mistake these unregulated stations will try to extract from you as much cash as possible.  The only reason they don't rip more people off is that there is so much competition that they are forced to arbitrarily lower their prices.  When getting a smog check make sure you get a quote up front, preferably in writing - I learned this lesson the hard way.  I went to the testers website and they had an advertised price of $46.  Naturally I assumed this was the price I was going to be charged.  Actually I was charged $98.  When I complained the man told me that this was the listed price on the sign at the station inside the station (which it was-written in small print and hung on the wall among a myriad of other items that were hanging on the wall).  Later I found out that he would charge many people only $46 but if he could get away with it, for whatever reason, he would charge more.