Regardless of interaction terms, the CBC/HB software recodes your design information into effects/dummy coding where each parameter is assigned a 1/0/-1 value, depending on the coding method selected. With main effects, your 6/6 design would have 5 parameters per attribute, for a total of 10 parameters. The omitted parameter is equal to 0 for dummy coding, and negative the sum of the other five parameters in effects coding.
When you add in the interaction effect between the two, we don't actually add in 36 additional parameters. Due to the coding we use, we can estimate the parameters as differences from the main effects, so your 36 combinations only actually result in 25 new parameters to estimate. These are coded using the same effects/dummy coding as main effects parameters, based on which combination of the two attributes was represented in that concept.
Linear coding converts the prices to zero-centered values as described in the CBC/HB help (from within the CBC/HB program, go to the settings for attribute coding and press "F1").