If you are just opening your Amazon account and not close to ordering products, then it is probably best to open the account initially as an individual account so you avoid the $39.99 monthly charge. However, once you to begin ordering products and selling you will want to upgrade your account to professional because amazon will charge you a $1 fee on every item sold which can really cut into you profit. The idea is you should be selling enough product to cover the cost of the $39.99.
If you need help on how to upgrade your Amazon account, there is another FAQ for that as well.
Here is a chart that thoroughly describes the differences between the two accounts.
Which account should I choose?
Is the professional selling plan or individual selling plan better?
What Amazon plan do I select?
