@ocelot60- You also need to find out about return shipping and handling costs before you make your online purchase. Some online stores require buyers to pay for return shipping, even if there is a problem with the items they purchase. This could be quite costly on an item the size of a tabletop convection oven.
To be on the safe side, you should ask if the online store provides free return shipping in the case of problems with their products. This could save you a lot of time and money in the event of an issue.