Database Design for Maintaining Supplier Invoice
Don't worry about having too many transactions in your table.  

Relational Database Management Systems like MySQL are designed to handle amounts of data that would overwhelm other formats, like a spreadsheet for example.

You can easily store millions of records in your table and MySQL will find you the ones you want quickly, especially if you define indexes on the fields that will be part of your WHERE clauses in your queries.  For example, if you want to do monthly reporting, make sure you have an index on transdate.