Commercial pricing generally depends on the mission you want to purchase (each has its own pricing packages), on the area size in km2 you need and how many acquisitions you need for the same area. The quota cost is calculated as a combination of the sum area in km2 and the number of acquisitions, with each additional acquisition duplicating the cost. Just to illustrate, a Pleiades quota package will cost you 100 euro, giving you 11 km2 to process, which you can use in the following ways:
An exception to this model is Planet PlanetScope, which has a Hectares under management model. It means that you subscribe to a parcel, then get all the archive and fresh data for one year for that parcel. 1 quota package includes 100 ha to process, and for this 100 ha the package includes all the available products free of additional charge. Pricing for PlanetScope thus depends on how big of an area you need to monitor (if you need 300 ha, you would buy 3 quota packages), and which of the three tiers you need (this depends on the country where your polygon of interest is located).
Note that commercial products are clipped to your polygon.
See commercial pricing packages here.