generally, the price submitted must match the displayed price, exactly.
and all variants submitted must be crawlable by all google's crawlers
if the price does not match for a variant then, the choices are usually:
(a) use a server-side solution such as php, python, etc;
(b) do not submit any variants -- submit only the (variant)
item that matches the default (price) on the page exactly;
(c) do not submit the item as a shopping-campaign but use
other campaign-types and ad-formats to advertise the item.