What do you mean by simple ecommerce? Do you want to sell a few products, a membership, consulting service, etc? I can make a more specific recommendation if I knew a bit more details.
I'll say that personally I have enjoyed using Wufoo for some simple ecommerce needs - just sync it into Paypal or Chargify and you can create a simple sales form. You may want to consider something like that. Gravity forms also has a paypal integration, but a bit simpler.