The mounting blocks are very inexpensive at less than $5.00 each with the mounting hardware included. The tilt /swivel brackets with an included mounting block are a bit pricey at $69.00. Rigid bracket with mount is only $22.50. You can buy direct from L&W. To do so, you'll have to call them and they'll set you up an account. Once the account is set up, you can log in and see all of the pricing online. By their own admission, they're pretty crappy at marketing so a lot of people don't know about them.
Ode to the Forum Moderators
May the Mods grant me the serenity to accept the opinions of those I cannot change,
the courage to offer valid input to those who are open to another way of thinking,
and the wisdom to shut myself down whenever I get too in love with my own misconceived brilliance.