Review the item:
Clarence could not believe that the hardware store was selling garden rakes
for only $1.99 each when he brought home twenty
of them, his wife Marie just shook her head and squeezed them into a garage
stuffed full of her husband's other "good buys."
A comma splice occurs when two complete sentences are incorrectly joined with just a comma. In the example above, no such comma exists. Clarence could not believe … begins one sentence. When he brought home twenty of them, his wife Marie just shook her head … starts the second sentence.
Because only empty space exists between the two sentences, you should call this error a fused sentence.
To fix the problem above, you could put a period after each and begin when with a capital W.