This is my standard recipe- but I usually use a bar of Ivory soap. I did buy a bar of Fels Naptha for my next batch and it is already scenting up my laundry room. Has a much stronger scent than Ivory. Smells clean, though.
You can sometimes find washing soda at your local hardware (like Ace) store. I did see that my Walmart has started carrying it in the laundry aisle now.
I have an HE washer and have no trouble.