Purchase Receipt without Supplier's invoice

Many times we receive material without Supplier’s invoice (only with Supplier’s delivery challan), can we create a Purchase Receipt without rate? what will be the impact if we do without rate or rate as 0? Do you foresee any issue with this?

The objective is we want to update the stock availability on receipt of the material.

that will affect your inventory values , if you use manufactureing… it will also affect your cost calculation in BOM