I have a couple questions. First, if a pet a carried trait what are the chances their offspring will get it? Second, what are good breeding prices? Thanks!

I'm not really sure, if I'm right, but as I know, the offspring can also have the carried trait, also carried. If both parents have the same carried trait, there's also a chance, that the trait will be visible.
The second question isn't that easy to answer. It's because many people put different prices, some do only 1 gold, some people set up specific prices for each trait and so one... If the pet is really rare, then the breeding price would be higher than of a less rare pet. If the pet is non-themed, but a project pet, the price would be also high. So as you see, the prices can depend on many things. You might do breeding prices, which aren't too high, but also not too low, if that's good.
I hope, I could answer your questions :D

To add to Candela, and give you actual numbers, if a pet with a carried trait breeds, there is a 50% chance it will pass on that carry. Other numbers would be...

Both parents have a carried trait in the same slot: 25% chance the offspring have a visible trait. 50% of carry. 25% of nothing.
A parent carries and the other parent has a visible trait in the same slot: 50% the offspring will have a visible trait. 50% of carry. 0% it will have nothing.

It might be a bit easier if you take the letters of the trait: Say, your pet has a carried trait "C", so on their profile it will say NC. N is basically nothing - and there is even odds of passing on one of those letters, either N or C! Two letters that aren't N make for a visible trait :) They can be the same, or different. In that case, the letter that comes first in the alphabet is a so called "dominant trait" and will be the one that is showing.

It might be a bit much for the beginning but I hope it helps!