Well, it varies by location. Some Walmart stores have a decent selection of comic books, while others might have only a few or none at all. It's kind of hit or miss.
Not always. Comic Pears may be available at Costco, but it's not a guarantee. You might need to check your local store or their online inventory to be sure.
Yes, you can usually carry a purse into Savannah Comic Con 2018. But it's best to check their official rules and guidelines for any specific restrictions.