An asking price is what a seller wants. A sold price is what someone actually paid. A price-guide estimate is a separate figure worked out by that guide.
Match first, then compare
Match the card version or sealed product first. Then check condition, raw or graded where relevant, quantity, currency, shipping and when it sold.
One sale isn't the market
A single sale can be unusual. A few relevant sales tell you more, but there's always some uncertainty. A low price on its own doesn't make something a bargain.
About the prices here
Prices in the academy's practice cases are invented. Use them to learn the method, not as a price guide.