It is not so simple - if you have read normalisation you should be able to relate this question to a normal form.
Based on what you have put in your question then absolutely not. However, if there is more to this then the answer might be "yes". Also, there is a further consideration not related to normalisation that might cause you to want to do what you propose.
So, given that - let's step through this together.
Originally Posted by i8grand
Am i right in saying that if a table has a field that has certain objects in it that repeat then another table should be made in which these objects do not repeat
Why not tell us why you think this and also what normal form this relates to
Should another table be made, maybe called tblSeller where there is a list of the sellers? And if so is just one field enough in the table or should there be another?
no, you do not have to do that, the only reason you'd want a sellers table is to enforce raltional integrity so that it will disallow inserting any rows into the tblItem tabletable which contain an invalid seller
if you wanted to allow any sellers at all into the tblItem tabletable, then you wouldn't need the seller table