Currently, these are the two solutions:
Fixed-price
Fixed-price would allow an item to stay the same price even if it changes in supplier (either price been increased or decreased). You can learn more about how to set up fixed-price here.
Set up a different Sku Grid account
Setting up a secondary account will allow one to have different settings than the first account. On the second account the "Auto-update price" could be set to No in that way Sku Grid only monitors and changes your items' stock level. Please note that if you would like to use this approach the items should not be duplicated in both accounts, and you would need a second subscription for the second account.