"Remote Scanning" only completes a preliminary survey - which is really just telling you what you need in order to look over the place properly. It's worth nothing on it's own. (Tbh, this skill is not all that useful.)
In order to get money you need to go to a planet and survey it, and then sell the data you generate.
Class I = ~1,000cr
Class II = ~5,000cr
Class III = ~20,000cr
Class IV = ~50,000cr
Class V = ~150,000cr
The higher the stability of the market, the more money you get, and vice-versa.
So basically; scan stuff, sell the results to Sindria.
When surveying it also helps to have several ships loaded with survey equipment (hullmod) to reduce the costs. Shepherds get this built in, and civilian freighters/tankers can usually carry it easily with no loss in utility.
Shuttles also work if you have nothing else available.
With enough survey equipped ships the costs for scanning each planet go down to 5x each machinery & supplies. (Machinery is a requirement rather than a cost.) Crew requirements never change.