The cost of this bag is $10:

1. i paid $10 for this bag.

2. the bag will be sold at around $10

3. this bag is priced at $10

what is the answer?

3. This bag is priced at $10

Explanation:

1. Is how much you paid not was it costs

2. The key word is around but in the statement about it says firmly that it is in fact $10

3.) It says what the bag is priced at so it's the only one that would make plausible sence.