Theoretically, they have to issue 1099's only when a vendor/contractor is paid over $600 but many send them for all. They are required to get a W-9 from you for this which must contain either your SSN or a TIN/EIN. I don't like giving my SSN out, so I get a TIN from the IRS and use that.

I will look into getting TIN

I've been a contractor for many years but only learned in the last few about the benefits of a TIN/EIN. It took me only a few minutes to get one.

so I'd wait for the client to ask for the tax I.D. number.

If you have a small business, consider getting a business tax I.D. number. You won't have to provide your SS#.

I am not obligated to provide it -- is that correct (if less than $600) ?

But should they ask for it then you'd have to give it up -- they could stop working with you.

...always good to have confirmation from a tax guy in Texas!!