Online store of video cameras and software (about 30 positions)

You need a one-page online store on Bitrix or Opencart.
The main task of the site is to automatically generate an invoice cost calculator.
About 30 positions.
We will send all the information.
From a freelancer - design (you can simple - emphasis on functionality), a bunch of effects are not expected.
Layout.
Domain
connection to the metric, I direct, callback setting (questionable)
About us: We sell video cameras, software.
The term is a small week maximum.