And it is precisely why the general recommendation for new shoppers is that they sign up with the basic companies: Market Force, CORI, Maritz, Bestmark, Trendsource, Service Intelligence. These companies are likely to have work most anywhere in the country because of the size of the chains they service. If you have a McDonalds, an Office Depot, a Home Depot or a Staples in your area, you will likely find work with these companies. We all know that these companies do not pay the best in the business, but they are accustomed to working with new shoppers, generally offer decent training/instructions and give a new shopper the opportunity to see if the basic notion of mystery shopping works for them.
If it works, then use Jobslinger to find companies that have recently shopped in your area because at least you know they have a client near you!
To sit down and start registering with every single company on whatever list you are using before you have received your first payment is an act of quiet desperation. There are companies out there that will not give you the time of day until you have shopped for a significant amount of time and done a variety of shops. To sign up with them too early is a kiss of death because you only get to register once. Your only salvation with them is to go back later, once you have some experience under your belt and update your registration in hopes they will look at you again.
And even with those companies in your area there will be variation. As Steve points out, not every one posts work to their job board. In fact some of them don't even have a job board. During the past year or so the majority of jobs for the month get posted the last week of the previous month or the first week of the current month. If you sign up today you are not likely to see the jobs because they have already been taken and likely performed and reported already. Then there is the qualitative screening. Prophet4 companies seem to need to specifically allow you to see work and self assign rather than letting you see it all but not be able to self assign as with SASSIE companies. But I have seen emails from SASSIE companies that the jobs were not on the board but available through the link sent. Go figure.
I am signed up with about 200 companies. In any given year I work with 30-40 of them. Whenever I see a new-to-me company that appears to be legitimate I sign up, though often these are such niche players that they only have work in their neighborhood. It takes a fair amount of money to tackle a large client and most companies do not have the wherewithal to tackle a Burger King, Wendy's, Bank of America, Ford or Exxon on a nationwide basis.