make price info screen for POS PHP codeigniter system

i have Point Of Sale system build with PHP codeigniter Mysql and well documented and very clean code i just need to make page have one field and browser will autofocus on this field user will scan item barcode buy scanner and price will display and if user scan another one price will change depend on item just very very simple page
with one big field
system have controllers well coded and clean and documented
i/m not willing to pay much it's very simple task