Looking for a cost efficient virtual book keeping service for simple Amazon business – any suggestions?

Hi all – I am looking for a cost efficient book keeping service my for an LLC that I manage. It is a very simple amazon seller business with almost 100% of transactions going through a single bank account. Ideally they can also create annual reports and file federal corporate taxes (if needed). Most services that I talked to start at $500 / month, which would be very disproportionate to the work required at this point. I was expecting to be able to find a lot of off-shore based companies but have not been able to find them. Curious if anybody has suggestions. Thanks!