Feedback on the potential limitations of our database design

My team and I are new to database design and are looking for some feedback on how we have built our tables and how we should build them in the future. We have multiple vendor master pricing tables built with the structure I have included below. The ITEM_NO is used as the key field on each table. Our original reasoning for having multiple tables with the same structure was to account for the potential that different vendors might share the same Item number for different items. This is rare but has happened.

The original intent for these tables was to create a tool that compared our stored master prices to the prices actually charged to us when we received the vendor bills. This data is stored on a separate table and we use the item number to JOIN the tables and price verify every item on an invoice. With our current database structure, this has worked very well.

We are now in the process of using the MANUFACTURER_ITEM_NO field to begin comparing item prices across the different vendor master tables. We have managed to create a query that does this successfully.

Eventually, we would like to use this information to automatically generate vendor purchase orders based on the best available price option for every item we buy from multiple vendors.
So far, everything we have built has worked but we are a bit concerned about certain aspects of our database design. We think now that we could have configured the Vendor Master tables to all exist on the same table. We are also not sure if there would be any issues storing the shared manufacturer information on the master tables vs a separate manufacturer items table that is then used in a JOIN query to create price comparisons. Should we not be concerned with the database structure as much as long as its working?

tl;dr We have designed our database based on then current needs and are now not 100% certain if the current structure will limit us in the future.

Any feedback at all is appreciated and please let me know if there is any more detail we need to add here.

M12345 FAUCET $20.00 MANUFACTURER1 12345 $15.00
M23456 SHOWERHEAD $25.00 MANUFACTURER1 23456 $10.00
K8463D SHOWERHEAD $30.00 MANUFACTURER2 8463D $15.00