If you can't afford the real class, then you can't afford it. I would be upfront about the cost issue in interviews and make clear that you are more than willing to take the class, if they insist that you have the certification (they should), but that you can't afford it. Some employers will cover the cost (they should if they're requiring it) or they may be willing to front you the money and deduct it from your first paycheck.

Considering the fact that you have to renew every two years, I think taking online class is fine if you've taken a in person class in the last 5 or 6 years. I took my last two classes online for $15 and the certification doesn't say anything on the card about it being a online class.

Whether they ask or not is irrelevant. Op won't know how to properly do it that's what's relevant here