I can only answer the first question about the GEOS projection.
The GEOS projection displays the earth as a geostationary satellite would see it (this is where its name comes from). Geostationary satellites orbit the Earth with an orbital period that is the same as the Earth's rotational period. To be able to do that, they are placed directly above the ...
I'd take a lookt at Planet. They offer three different resolutions (1, 3 and 5m). You can get a free-trial and check if it fits your needs.
For the costs, maybe check this conference paper that does a benchmark of different satellites or this pricing information for reference.