A lot out there to choose from in the store...
I buy on sale and mix with homemade sauce for layers of flavor.
I use or mix with these...
1) Stubbs (thinner not sticky sweet)
2) Sweet Baby Ray's Several Varieties
3) Razorback Mild http://www.rivercityspice.com/bbqsauce.html
$11.00 a Gallon I use this for Events and parties as a time and labor saver.