Please see my answer below..
From stock entry screen I don't see any way to link a
product to a supplier as it only have the manufacture field.
Ans: No we didn’t link directly from stock to supplier other
than through Purchase menu..
Also how about adding a stock item from an new invoice with
a diff price and having same barcode from manufacture ( like normal price
increase in market).
Ans: You need to update the stock with the price. This
situation will not come normally as the product will be bar coded with a new
number..
Is there any way I can import product data in bulk?
Ans: If you have the data in excel
sheet , the we will be able to help you with importing the data to SalesMate +
(Additional Charges apply)