Begin at the R2 Launch Pad.
Click on the Account button.
Click on Search → Items.
Use the search criteria to locate the item you wish to setup pricing for.
Right-click on the item you wish to setup pricing for and click on EDIT.
Click on the Pricing button.
Click on the Add button.
Select the date this price will go into effect.
Select the Unit type:
Daily, Weekly and Monthly types are for rental orders.
Enter the Price (this is based on the Unit type).
Enter a Cost (per day/week/month cost you ascribe to each rental item).
Click on OK.
Add a price for each unit: Daily, Weekly, Monthly. If the item is also for SALE then use the unit of EACH.
Click on the Exit 
Repeat steps 4 and 5 for setting up pricing on additional equipment.