Excel Formula to sum the values from one column only if there are values in another column?

This is hard for me to explain and I'm not an expert. Sorry if this is confusing.

I have a worksheet that lists several items a customer could buy and I need the worksheet to create price and cost totals depending on what items they select. I have the price total but having issues with the costs because I only need the sum of the costs for items that have a price in the respective cell.

Below is a small sample of my table. Basically, I need a formula to sum up the cost (column B) if there is a price in Column C.

I started doing this but the string would be insanely long: IF(C2<>"",B2,0)+IF(C3<>"",B3,0)+... Is there a formula to make this work for several rows together?

See sample here.

If you recommend doing something completely differently, I'd love any suggestions.

Thank you for your help.