JB,
$10-15 per person? For app, entree w/ sides, dessert, and 2 beers? I dunno, I lived in Houston and Atlanta for a lot of years and have eaten at tons of small-town places throughout Texas, and $10-15 for that still seems absurdly cheap.
Having said that, you can pretty much double the price of dining out at similar-level places in SF or NYC as compared to cities in the South, but everything costs a lot more out here.
Cajun/soul-food/"country cooking" is not a super-common category, but every city definitely has a few, ranging from shacks in bad neighborhoods to "upscale" versions in the city.
Here's a pretty legit place in SF:
http://powellsplace.ypguides.net/
Here's an "upscale" place in SF:
http://www.farmerbrownsf.com/
Here's an even "higher end" place in SF:
http://www.theelitecafe.com/
I've been to Powell's and it's f'ing great. I've been to Farmer Brown and it was OK. Angeline's is somewhere in the middle in terms of niceness and price, but far superior to Farmer Brown. Haven't been to Elite Cafe.