First you need the material master with accounting view & Plant data storage view. In the material master you must maintain the Price control as either "V" or "S" as per your requirement with the Value as per that.
Then for Initial upload use Transaction MB1C with Mvt type 561 for initial stock upload into SAP.
Enter the Plant, Storage location, Material no, Qty to upload.
Prices are maintianed in the Material master check in MM02/mm03 for that particualr materials.
You cann't maintaint the price in MB1C.
If you don't maintained the price in material master then in MR21 you need to maintain the correct price with the help of Finance department.
plz check following
in this docs u will get proper idea to do the opening balalnces for quantity and value
now when u put price control S or v in ur MMR then system will pick the price u have given and multiply it with stock u have updated with movement 561
like u have given 50 inr/kg (price control S or v )
and stock will update as 100 kg then system will give u the cost as 100kg *50 inr =5000
rather than this suppose u have the stock of 100 and the total value is 50000 inr
now u have to calculate the per kg price as 500 inr ,now give this is value in MMR or change the value in MR21
then do the movement 561 u will get exact value of 50000 inr
try this inur dev server
the price for initial stock will update inspite of ur price control but with the price u have given in MMR
hope it clears